Foot-pounds or pound-feet? Either gets the message across, but technically only one is correct for fastener and engine torque.

Parts Sources

Suppliers

Special Tools

Special Tool Lists & Illustrations Tool icon

Other Online Resources

Triumph Models Manual icon

Online Forums

Classic British MC Links - All links No ads

General Shop Info

Abbreviations

Left-Hand Threads

You've leaned on it, heated it and pounded it and that part STILL won't come out! Duh, it's a left-hand thread! Don't drive yourself nuts, consult this illustrated list of the five left-hand fasteners on a 1969 Triumph 650. Or look for the left-hand signs below in The Bonnie Ref.

British Motorcycle Fasteners: Threads

SAE threads

UNF

UNC

The British standard threads

Note that while American wrenches are measured across the flats (AF) of the bolt head, wrenches for the bolts in the British standard thread family are measured by the diameter of the bolt's threads.

CEI/Cycle/BSC

BSF

BSW

BSPP, BSPT

Wrench Jaw Gap Sizes

Loctite Thread Lockers

Where to Use Loctite

Where to use Loctite thread locker on a Triumph 650 is a question that will elicit different answers depending upon who is asked.

The Loctite Gospel: According to John

According to John Healy (see link above), there are just four places to use Loctite on a Triumph 650:

The Loctite Gospel: According to Thomas

Thomas G. Gunn, Jr., in his seminal 1987 work "Overhaul Manual For 650cc Unit Construction Triumph Motorcycle Engines since 1963", suggests using Loctite in six places:

It's interesting to note that out of John Healy's four places to use Loctite and Thomas G. Gunn Jr.'s six places, the only concurrence between the two lists is the crankcase bolts.

Other disciples have suggested using Loctite on crankcase studs, although in that application it's used more as a sealant than as a thread locker. In addition, amateur Loctite enthusiasts (now who said that?) have devised many other ingenious applications as well.

Loctite Thread Locker Characteristics

The most popular Loctite thread locker products (also see chart below for typical applications):

Loctite Red

Loctite Blue

Loctite Purple

Sealants

Sealants: Where? and What Kind?

The following chart, an interpretation/extrapolation of the TriumphRat.net links above, summarizes opinions about which sealant and which thread lockers to use, and where. Green dot items are commonly recommended, while yellow dots indicate that extra caution is required. Red dotted scenarios may best be avoided altogether. Rationale for the classifications should be apparent from the product descriptions that follow.

Sealant Product Characteristics

Loctite 518 Sealant

Loctite 574 Sealant

Hylomar Blue Sealant

Hylomar M performs just like Blue, but its solvent is California approved. F/G Engine has an excellent write-up of several Hylomar products, including Blue and M. Very informative and lots of good practical tips. Read it and reap!

Three Bond 1130 Sealant

RTV Sealant

Wellseal Sealant

Gaskets

Bearing Retainer

Loctite Bearing Products and their Characteristics
Characteristics / Product	Loctite 641	Loctite 660	Loctite 620
Applications		Press fitting, repairing, retaining	High temp slip fitted parts, retaining
Color	Yellow	Silver	Green
Cure Type		Anaerobic cure	Anaerobic cure
Fixture Time	20 min.	15 min.	60 min.
Gap Fill	0.15 mm	0.25 - 0.5 mm	0.15 - 0.25 mm
Strength	Medium strength	High strength, gap filling, thixotropic	Medium to high strength, gap filling, high temperature, high viscosity
Operating Temp	55 - 150C (-65 - 300°F )	-65 - 300°F (-55 - 150°C )	-55 - 230C (-65 - 450°F )
Format		Paste	Liquid
Substrates	Metal: Steel	Metal: Steel	Metal: Steel
Removal			Requires heat

Assembly Lube

Assembly lube products are designed to provide lubrification to moving engine parts during initial start-up. An important advantage of assembly lube over motor oil is that while oil will drain away from parts relatively quickly, assembly lube coats parts and remains in place pretty much indefinitely, thus eliminating the need to compress the time between assembly and initial engine start-up.

In the TriumphRat.net thread above, Peg suggests using assembly lube for big ends, piston skirt (very sparingly), cam lobes and bushes, tappet blocks, rocker arms, and valve stems.

Applying Heat

Lubrication

Routine Maintenance & Lubrication

Engine Lubrication

Diagram of Triumph Unit 650 Engine Lubrication System

Selecting an Engine Oil

According to an article ("Tech 101: Zinc in oil and its effects on older engines"), modern oil manufacturers have reduced the amount of 'zinc' (actually ZDDP [zinc dialkyldithiophosphate] or ZDTP [zinc di-thiophosphate]) in their products for various reasons, including prolongation of the life of catalytic converters. When used in older (classic) car and motorcycle engines, the low-zinc products fail to provide sufficient protection against start-up engine wear.

Here's a list that gives zinc content of a few oils on the market, In relatively cool climates, Shell Rotella 15w-40 seems to work quite well.

Changing Engine Oil

Triumph specified an engine oil change interval of 1,500 miles. Of course the only oil filtering back in the day was the wire screens in the oil tank and the crankcase.

Even after I installed an external oil filter (see "Using an Oil Filter" just below), I continued changing engine oil (and filter) at 1,000 mile intervals. And to simplify things I change crankcase oil and primary chaincase oil at the same time. So far, oil changes are cheaper than engine rebuilds!

Some point out the difficulty in cleaning thoroughly around the crankcase oil drain plug due to its proximity to the crankcase joint and the angle at which they meet. They suggest that removing the crankcase drain bolt is a bad idea because of the attendant risk of contaminating engine oil with dirt.

Since only a small amount of oil (less than a quarter of a cup) drains out of the crankcase anyway, I adopted the practice of removing the drain plug once a year during winter maintenance to inspect and clean the filter screen. The same goes for the filter screen in the oil tank.

Using an External Oil Filter

Probably the single most important modification one can make to a classic British bike is to install a modern external oil filter. It has been said that doing so can quadruple the life of an engine. That estimation may be slightly exaggerated, but there's no doubt about the extra protection afforded to an engine by an add-on oil filter

The most common retro-fit oil filter system utilizes a Norton-type oil filter head, connected in the return oil line between the oil pump and the oil tank, as diagrammed below.

The go-to mounting bracket design is that of Glenn Davidson (see link above). The oil filter head and Davidson-style mounting bracket are commonly mounted at the bottom of the down tube, facing the rear of the bike at a height which gives just enough clearance between the filter and the center stand in both it's up and down positions. It may be necessary to grind just a bit off the "lump" at the bottom of the downtube.

Note that the Triumph oil tank connections and oil pipe junction block pipes are 1/4", while those of the Norton filter head are 3/8". The compromise is to use 5/16" (automatic transmission cooler) hose to make the connections between the filter head and the oil tank and oil junction block. It is a very tight fit on the filter head's 3/8" fittings, and somewhat loose on the 1/4" pipes of the oil tank and oil junction block, but once they are well-clamped the connections shouldn't leak.

Another possiblity is to replace the Norton filter head's 3/8" stubs with 1/4" ones. This mod was performed on my Bonnie's filter head recently so now I use 1/4" hose throughout.

Filters for use With standard Norton filter head

The following filters work satisfactorily with the Norton filter head, and others can be found on cross-reference lists online.

Colorado Norton Works Filter Adaptor

A simple double-threaded adaptor is available from Colorado Norton Works (see link above) which permits use of more widely available and potentially less expensive oil filters, such as the following:

The Oil lines

Oil Line Connections for Stock Condition - No External Oil Filter

The oil pipe junction block connections described here are only for Triumph unit 650s. No less an authority than Mr. Pete informs us that connections for pre-unit Triumphs are the exact opposite.

In the following descriptions of oil line connections, "front" and "forward" reference towards the front of the motorcycle, and "rear" and "back" reference towards the rear of the motorcycle.

Feed Oil Line

The feed line is the rear oil line connection on the oil tank (union nut). The feed line goes to the forward connection pipe on the oil junction block. So oil tank rear to oil junction block forward. (Refer to illustration just below).

Return Oil Line

The return oil line is the front connection on the oil tank. It goes to the oil junction block's rear connection pipe. So oil tank front to oil junction block rear. (Refer to illustration just below).

Scavenge Feed to Rockers

Oil to the rockers was fed from the oil tank tower in 1966 - in all other years, before and after, the feed is taken from the scavange return at the bottom of the tank. Illustration of Triumph oil line connections without an external oil filter

Illustration of Triumph oil line connections without an external oil filter

Oil Line Connections When Using a Norton Filter Head

A Norton oil filter head is ordinarily installed in the return oil line as per the following diagram. Illustration of Triumph oil line connections for add-on oil filter

Illustration of Triumph oil line connections for add-on oil filter

Removing Oil Lines at Oil Junction Block

Removing the oil lines from the oil junction block tubes can be a bit difficult, especially if they have been undisturbed for a long time. The job can be made a little easier by removing the outer gearbox cover first.

In any case, it is wise to heed the WS Manual's explicit warning to avoid over-stressing the tubes.

Crankcase Breather

A 3/8" plastic tubing (70-5375 Ref# 39 Fig.2 #7) connects the engine breather pipe stub (70-2724 Ref# 7 Fig.2 #7) just forward of the gearbox sprocket to the Tee (70-5370) near the top of the oil tank. Also connected to the tee is the oil tank vent pipe ( 70-6356, Ref# 16 Fig.23 #7), and the oil breather vent tube (82-7353, Ref# 18 Fig.23 #7)

Oil Breather Vent Tube

The oil breather vent tube passes on the left side just above the indentation in rear fender.

The first clamp is fastened on the left-hand side beneath the left nut holding the strap on top of the fender between the two upper shock mounts.

Oil Pump

Changes in Triumph Oil Pump Specifications Over the Years
Year	Part No	Specs
1963 - 1966	E3878	Scavenge 0.437"/ Feed 0.374"
1967 - Early 1969	E6928	Scavenge enlarged to 0.487"/ Feed 0.374"
Late 1969 - 1979	E9421	Scavenge 0.487"/ Feed enlarged to 0.406"
1980 and on	71-7317	Double check-valve pump (Scavenge& Feed unchanged: Scavenge 0.487"/ Feed 0.406")
Source: Britbike.com

Oil Pressure Relief Valve

Oil Pressure Switch

If so desired, the oil pressure switch can be removed and replaced by a blanking plug.

When fitting either a replacement oil switch or a blanking plug, care must be taken to insure that its threads correspond correctly to those of the timing cover. Most timing covers are made for straight threads, but threads in some are tapered. Consult the links above to determine the correct part for your bike.

The Oil Tank

Problematic Oil Tank Design - 1966

Removing Oil Tank

Replace Oil Tank

Oil Tank Mounting Adjustment

One would think that the rubber mounting would incur the wear, but the wear that occurred after my very first re-assembly was to the tank's mounting peg, not the rubber.

A proper adjustment is obtained by rotating the "C" clamp mounting bracket until all parts of the tank are suspended clear of the frame.

Oil Tank Mounting Measurements

In case you ever need to know, HenryAnthony on Britbike.com forum informs us that the measurement between the barrels holding the rubber upper mounts is 4-1/4", and the measurement between the battery holder straps they bolt up to is 4-1/2".

Wet Sumping and Oil Drain Down

Primary Chaincase Lubrication

Owners of Models Late-1969 & On - Read This

Primary Chaincase Oil Change (Engines not sharing crankcase and chaincase oil)

Change primary chaincase oil at 1,000 mile intervals. Drain and replace with 350cc of 30w non-detergent oil.

As noted just above, a fairly common practice is to replace non-detergent primary chaincase oil with ATF - but NOT on units that share oil between engine and primary.

Draining the Primary Chaincase Oil

The chaincase oil drains slowly because it needs to flow past the primary chain tension adjuster. The drip, drip, drip flow of oil even when it's hot takes hours so I usually give it all day or overnight.

Gearbox Lubrication

Gear Oil Compatibility

Opinions differ about using GL5 spec gear oils around the yellow metal bushings and thrust washers used in our Triumph gearboxes.

GL5 oils have high concentrations of sulphur and sulphur reacts with yellow metals chemically to break them down. So say those who believe GL5 is harmful. Yet many others say they've used GL5 for years without problems.

Why take a chance? I was always disinclined to use GL5 gear oil in my Bonnie's gearbox.

Oil companies say GL5 products are now safe because they've reduced active sulphur, which eats yellow metals, in favor of inactive sulphur, which is less harmful while still providing the protective qualities of active sulphur.

Potentially Harmful Products

For those who harbor doubts, the following list of oil descriptions are those which are said to be, at least potentially, harmful to yellow metals:

For other gear oil recommendations (including many in UK) see this link above in TriumphRat.

Oil Change Schedule

Draining and Replenishing the Gearbox Oil

There are three hex heads on the bottom of the gearbox: the 3/4" index plunger holder (57-2172); the 7/16BS (3/8W) drain plug with level tube (57-3851); and the 5/16" gearbox level plug (21-0543).

The level plug threads into the drain plug and together they are tucked just inside the frame member on the timing side. Since they are closer to the timing side I always removed and installed them from that side. However, access from that side is awkward due to the proximity of the frame, and recently I realized that it's actually easier to access them from the drive side.

To drain the oil, remove the drain bolt using a 7/16BS (3/8W) socket and a two or three inch extension to clear the frame. Remove carefully to avoid damage to the level tube extending above the drain bolt.

When replenishing the gearbox oil I simply measure out 500ml in a graduated container and add it through the gearbox outer cover port. You can also use the level plug to gauge fullness, but it requires patience because the heavy gear oil does take some time to work it's way through the slender level tube.

Oil Leaking from Drain Bolts

Front fork

Draining Fork Oil

Contact Breaker Assembly

Speedometer Gearbox

Note that the nipple on the speedometer gearbox grease fitting is not a standard size. However, a standard grease gun will inject a sufficient amount of grease to keep the gearbox well-lubed according to Stuart.

Swinging Arm Bushing

The Engine

Pre-Ignition & Detonation

Descriptions of pre-ignition and detonation found in the article and video above can be summarized this way:

Engine Temperature

Here is a chart of Triumph 650 engine temperature readings taken as the engine warmed up to operating temperature. Fairly typical for ambient temps shown.

Kicking Back When Starting

Kicking back during starting is symptomatic of engine problems and potentially hazardous to the operator. The three most likely causes of kick-back are:

When considering timing advance issues it's wise to first check the alignment of the rotor's 38 degree line with actual TDC using a TDC tool or other method.

Spin speed can be a factor, particularly in the case of electronic ignition systems.

Engine Removal and Installation

Crankcase

Crankcase Junction Studs

Crankcase Cylinder Base Studs

Remove studs using two locked nuts. Don't use the 12-point base nuts, instead use a couple of 14-0303 nuts (3/8-24TPI UNF) - there are 10 of them on 1969 and later 650s - can't hurt to have a couple of spares on hand. If studs resist removal, some gentle heating of the case should release them pretty easily.

The two primary side inside cylinder base studs have locating hollow dowels on them, and the threaded holes for the two timing side inside studs are through-drilled on the 650's. These should be sealed in order to prevent oil from wicking up the stud threads.

(Note that on T140 crankcases the two outer studs on the drive side are through-drilled.) '69 Triumph crankcase cylinder pad showing hollow dowels and stud holes that are thru-drilled

'69 Triumph crankcase cylinder pad showing hollow dowels and stud holes that are thru-drilled

Crankcase Hollow Dowels

Several parts books, including #7, make a mess of the part numbers, locations, and quantities of these dowels. All the errors are described and corrected in this corrected illustration.

Parting the Crankcases

This procedure is after that shown by Hughie Hancox on his "Hughie Hancox Triumph Unit 650" rebuild DVD.

Reassemble the Crankcases

Crankshaft

Sludge Trap

The sludge trap is a metal tube fitted inside the gallery that runs through the big end connecting rod journals. Oil is forced through the timing end of the crankshaft and through oil passageways into the sludge tube. There, centrifugal force separates the particles suspended in the oil - think of a washer in spin cycle with bras and panties flattened while the water flows away. Well, maybe not such a great analogy. Anyway, inboard weep holes permit the oil to lubricate the big end bearings and then return to the crankcase sump from where it's pumped back to the reservoir.

Although it's controversial and frequently maligned, the Triumph sludge trap is actually a relatively effective oil filter. Its big drawback is that it can't be inspected or cleaned without splitting the crankcase - a major job requiring complete disassembly of the transmission and engine, although not necessary the gearbox.

Some believe that no matter how full the sludge tube becomes, oil under pressure will always make its way to the big ends.

That's a theory, but the more widely accepted notion is that a plugged sludge tube will prevent oil from flowing to the big ends with catastrophic results.

It's also widely held that after a bike sits for a long time and is then restarted, dirt particles in the tube may break off and subsequently block critical oil ways in the engine, there being more risk for machines lubricated with non-detergent oil before storage and then drained and re-filled with detergent oil before re-starting.

So without splitting the cases, how does one know whether or not the sludge tube needs cleaning/replacing? Unfortunately we can't answer this question precisely, we can only make an educated guess based on service history and engine condition.

Factors Affecting Accrual of Engine Sludge
More Sludge Deposit	Less Sludge Deposit
High mileage	Low mileage
Using non-detergent oil	Using detergent oil
Running dirty oil	Frequent oil changes
No external oil filter (as stock)	Fitting external oil filter

A sludge trap service interval of twenty- to forty-thousand miles seems about right for a well-maintained machine in good condition and fitted with an external oil filter. Without an oil filter (stock) one could expect a significant reduction of those figures.

On the other hand, it has been said that fitting an external oil filter quadruples the life of an engine, and it's certainly not unreasonable to expect that a sludge trap would fill more slowly under those circumstances.

Some suggest hypothetically that sludge traps on '70 and onward 650 Twins might fill up more quickly due to those models sharing oil between primary chaincase and crankcase and on the basis that the clutch produces even more sludge (think shock absorber rubbers) than the engine itself.

Sludge tubes can be quite difficult to remove as there are two hurdles: removing the cap, and removing the tube itself. Tubes don't always survive the extraction, caps rarely. However, replacement sludge tubes are not expensive. Also, caps for them are now available which have either hex heads or hex key sockets instead of the more difficult to remove slotted head on the stock item.

There are two ways to remove the tube: smack it out and pull it out. Pulling it out may contribute to higher rates of tube survival.

What size tap to use for tube removal? LowBrow video (link above) suggests 3/8"-18 N.P.T. Kevin suggests EZ-Out number 6, drill size 13/32-inch.

When replacing the sludge tube be absolutely certain that its alignment hole is actually lined up for the flywheel bolt before inserting and tightening the bolt (Grand Paul).

Flywheel

The three flywheel bolts are one of the four places to use Loctite on a Triumph, and the only place to use red Locktite.

Changes to Triumph Flywheels From 1963 to 1971
Year	Change
1963 - 1964	Heavyweight flywheel - no timing slots
1965	Slot for TDC added
1966	Lightweight flywheel Balance factor unchanged (85%)
1968	Lightweight flywheel Slot for 38 degree max advance timing added First ones also had extra slots for timing plug re-positioned to the front of the engine, but later reverted to rear position after DU74052
1969	Began w lightweight flywheel Reverted to heavyweight at NC.02256 - much like 1965 flywheel, but with 38 degree slot
1971	New flywheel - different profile Same balance factor and slots as 1969 flywheel Metric-sized timing side crank introduced at end of 1971 model year

Triumph Crankshaft Balancing

The kinetic energy of the Triumph 650 parallel twin's pistons, rods, and crankshaft is essentially the same as that of a single-cylinder engine - jumpy! Therefore, in an effort to reduce vibrations for the rider's sake, at least some of the "jumpiness" is removed by "balancing" the crankshaft.

Balancing a crankshaft is a two-sided coin: balancing for fewer vibrations (greater rider comfort) inherently increases mechanical stress to the crankshaft and bearings, potentially creating abnormal wear or even out and out destruction.

On the other hand, balancing for completely minimal mechanical stress results in vibrations intolerable to riders.

So balancing to begin with is a compromise. The compromise is governed by something called the "balance factor". In simple terms, the balance factor is a chosen percentage of the reciprocating weight of the engine's crankshaft, rods, and pistons. That calculated weight is then attached to the crankshaft as a counterweight as it is balanced, either dynamically or statically. The result should be a reasonable compromise between rider and machine stress.

The balance factor in the 1969 Triumph 650 Workshop Manual is 85%, which, based on stock crankshaft, rods, and pistons, works out to a nominal 689 gram counterweight for a 650 twin.

For the parallel twin, a balance factor of around 63% is said to create the lowest possible stress to crankshaft components. But of course that would also create very uncomfortable vibrations. Some say that Triumph later lowered their published balance factor of 85.

It's possible that certain riders on certain machines could be perfectly comfortable with something like a mechanically kinder 75% balance factor.

If a twin's crankshaft counterweights are out of balance from one side to the other it creates what's referred to as a "rocking pair". While a rocking pair can be completely balanced side-to-side, balancing up-and-down vertical vibration is, as already stated, a compromise between rider comfort (high balance factor) and reduction of mechanical stress (lower balance factor).

Using a balance factor, both static and dynamic balancing can adjust for up-and-down vibration, but only dynamic balancing can detect and correct a rocking pair.

Note that static and dynamic balancing are both done on "dry" crankshafts. The addition of oil, including in the sludge trap, is said to effectively reduce the balance factor by 2 to 3%. Some shops balance with oil in the crank and adjust for it.

Finally, consideration should be given to the type of flywheel: light, or heavy. The light flywheels (1969 only) were intended to spin up more quickly and offer more pep at lower speeds. However, they were said to idle more poorly than heavy flywheel models, and are said to be more prone to vibration and stalling on take-off.

DS Crankshaft Oil Seal

When replacing the DS crankshaft oil seal, note that there are differing opinions floating around as to its correct orientation. In spite of both the Triumph Workshop and Overhaul manuals clearly indicating that the spring side of seal should face the engine sprocket, i.e. the primary chain case, there are some (including John Healy, Todd of Lowbrow, etc.) who say this is incorrect. See the BritBike.com and Lowbrow video links just above.

Engine Breathing Method and DS Crankshaft Oil Seal
Year	Engine Breathing	Engine/Primary	DS Crankshaft Oil Seal
1963 - 1969	Timed engine breather	No sharing of oil	Oil seal required. Springs to engine sprocket
1970 - 1972	Breathes via 3 holes btwn crankcase & primary chaincase	Oil is shared	NO oil seal should be used, even though erroneously shown in the parts books (J Healy)

Main Bearings

Connecting Rods

Assembling Connecting Rods and Shell Bearings to Crankshaft Journals

It is very important to cover rod shanks for protection against nicks and scratches at all times. Nicks and scratches create stress points which will develop into cracks which will develop into disaster. Small nicks and scratches should be polished out with strokes made parallel with the rods using emery cloth and begining with #180.

Great care needs to be taken to mark and then reassemble connecting rods, caps, and shell bearings in their original locations and orientation. If components are new heed should be given to location if crankshaft was dynamically balanced.

Connecting rod caps and big ends usually have small punches or other marks that indicate how they are matched up. Often the marks are placed forward on the journals, but if they were assembled differently they should be re-assembled as they were. If a rod binds on the journal it's probably because the cap is turned around on the rod or the rod is turned around on the crank. photo of big ends with caps, shells, and shell tanngs aligned correctly

photo of big ends with caps, shells, and shell tanngs aligned correctly

Never put oil between a shell and its rod or rod cap - this area should be absolutely clean and dry. Always use an appropriate assembly lube between a shell and the crankshaft journal.

The shell bearings are pressed by hand into the connecting rods and their caps. When the caps are installed on the rods, the tangs should end up on the same side of the big ends as shown in photo to right. Otherwise the caps are on backwards and the rod will bind on the journal as noted above.

Note that the tangs do not fix the shells in place, they center the shells in the rods and caps, making the shells slightly and equally proud at each end. This way, when the caps are tightened down the resulting "crush" wedges the shells tightly into the big ends, preventing them from spinning. The slight bevel on the shell ends helps compensate for any distortion that might occur from the crush.

Shell bearing clearance (diameter clearance) for the 1969 Triumph Bonneville is listed as 0.0005" - 0.0020" by the Workshop Manual. A generally accepted way to measure the actual clearance is with "Plastigauge".

Updated Torque Spec for Connecting Rod Bolts

Distinguishing Between Older and Newer Connecting Rod Types

The Triump 650 Overhaul Manual says to measure the rod shank across the front or back 1" below the bottom of the wrist pin hole. According to the OHM, older style rods measure .550" while newer, thicker rods should measure .605". (Source: "List of Engine Changes Relating to Major Engine Work", Triumph 650 Overhaul Manual).

I've measured only one of my '69 T120R original rods - it was 0.606" on one side, and 0.596" on the other. Close enough for original.

Achieving Correct Connecting Rod Bolt Torque

Initially, tighten the self-locking nuts with an ordinary wrench until both sides are tightened down evenly and the rod spins freely on the journals. Then tighten the nuts progressively using a torque wrench or measuing bolt stretch.

Tightening connecting rod nuts to the proper torque can be accomplished using either one of two methods: using a torque wrench, or by measuring bolt stretch.

So while there's near universal agreement that the bolt stretch method is best, it is only possible if one is able to make the measurements with the required accuracy. To get a better sense of what this entails, check out this Britbike.com discussion.

In actual practice the most common choice is probably to use a torque wrench to tighten the nuts "dry" to the correct torque spec. This should work fine for new, good quality bolts, but perhaps not as well for used bolts, especially when their previous stretch is unknown.

Timing Chest

Removing Timing Chest Cover

To remove the timing chest cover you must first remove the auto-advance unit. See link just above for tips on removing the AAU with or without the D484T special tool.

Note that unless care is taken, the idler wheel can fall off when the cover is removed. Placing the bike on its sidestand may help keep it in place. If it does fall off and none of the other gears have moved, simply replaced it.

Disassemble Timing Chest

The cylinder head and the cylinder block have been removed and the transmission and gearbox have been disassembled prior to the steps below.

Removing the Crankshaft and Camshaft Pinion Gears

The main difficulty in removing the nut securing the crankshaft pinion gear is imobilizing the gear. That is the topic of discussion in this BritBike.com thread. This group of posters propose and debate several methods:

Jamming the timing gears with a rag is not recommended as damage can occur. If clutch and gearbox components are still in place, a clutch locking tool is the best choice. Otherwise, use a pneumatic impact wrench, or simply wait until the cases are parted and then use a vice with soft-jaws to grip the camshaft lobes and remove the nuts with a wrench.

Valve/Cam Timing

Replacing Crankshaft and Exhaust Camshaft Seals

Replacing the Patent Plate

The patent plate mounted on the timing chest cover often gets polished to a shiny blank. If so, or if it has been damaged, spare replacements are available. Note that some repro patent plates are embossed and others are not.

The trick to changing the patent plate is removing the twisted pins that hold it on. Being hardened, the pins are somewhat brittle, so care must be taken to not break them off, making extraction even more difficult. The links above describe the most popular techniques and also cover what to do should things go wrong. Kadutz, on TriumphRat.net wraps it up nicely.

Pistons

Removing Stuck Pistons

So, you landed that amazing "barn-find" but can't get the cylinder block off because the pistons are stuck. Here's a summary of methods to free stuck pistons from TriumpRat.org (see link just above in Resources for full details):

Chemical

Mechanical

Gudgeon Pin Removal & Small End Bushes

Gudgeon pins (wrist pins) should move freely (but without side-to-side play) in the small end bushes of the connecting rods, and be of a tighter fit in the pistons, Sometimes they can be removed with just thumb pressure at room temperature, but other times it requires a little heat on the piston: 100C (212F) using a digital laser thermometer or the spit sizzle method. Chilling the gudgeon pins can also help.

If a wrist pin won't come all the way out even after heating the piston, you can use a simple extraction tool fashioned from a threaded rod, a couple short lengths of pipe, and some nuts and washers. See link just above.

Piston Skirt Clearance

Skirt clearance is the amount of space between pistons and cylinder walls. Insufficient skirt clearance means near certain piston seizure.

It's possible to measure the clearance with feeler gauges but a more accurate method is to measure piston outside diameter with a micrometer and cylinder inside diameter with a bore gauge and subtract as follows:

The spec given by the 1969 Triumph Workshop Manual for piston clearance is 0.0106/0.0085 inches at the top of the piston skirt and 0.0061/0.0046 inches at the bottom. Top and bottom clearances are given because pistons back in the day were slightly tapered. John Healy offers us this explanation of the reason for the taper and why it's no longer of much concern.

Modern pistons are manufactured differently and have little if any taper, so clearance may well be the same top and bottom - all to be determined by careful measurements of course.

I think it's safe to say that when using modern pistons with effectively no taper, a top and bottom piston clearance of 0.005 to 0.0055 inches would be very acceptable.

Usually reliable sources have said on forums that clearances of 0.0041, 0.0037, and even less work for them, but for a variety of reasons those clearances are not apt to succeed on every engine built by any builder. The bottom line is beware of not enough clearance because the result is piston seizure.

Too much clearance? A noisier engine and probably increased wear to pistons, rods, etc.

Replacing Gudgeon Pins

Often gudgeon pins can simply be pushed in with thumb pressure. If not, either chill the wrist pin or gently warm the connecting rod small end where fit is likely the tightest.

Rings

Ring Gap

Different Triumph docs through the years gave different ring gap specifications. The last revision was made in 1971.

Ring Gap Changes Over the Years
Document	When	Recommendation
Triumph Service Bulletin Twin 11/71: Piston Ring Replacement	1971	0.012 - 0.018
Triumph Overhaul Manual: Page 10, Step (d)	1967	0.010 - 0.017
Triumph Service Bulletin #323: Piston Ring Gaps	1967 DU44934 H49837	0.015 - 0.020
Workshop Manuals, Gen Data and: Section B23	1963 - 1969	0.010 - 0.014

The important thing is to have sufficient gap: a little too much isn't critical, but too little can result in the rings binding up and scoring the cylinder walls or even seizing a piston in extreme cases.

Keep in mind that ring gap determination must be proportional to cylinder size, an important consideration if installing so-called big bore kits. Dave gives a standard formula for gap calculation based on cylinder size here. Don offers a slight variation here. That thread is worth reading in its entirety as it includes much good advice.

When filing ring gaps the ends should be kept parallel with the ring's radius. If using a file consider doing as Don does which is to hold the file in a vice and not the rings. Emory paper can also be used: some move the paper through the ring and others move the ring across the paper (see "DIY Piston Ring End Gap Tool" just above in resources for an interesting take on this).

Installing Rings

Always install rings from the top and observe correct order and cylinder for each ring. Rings usually have a marking that indicates which side goes up. Orient the oil scraper rings with their gaps at six o'clock, and the compression ring gaps at three o'clock and nine o'clock.

One advantage of using ring compressors is that the orientation of the ring gaps doesn't change during installation.

Cylinder Block & Tappet Blocks

Cylinder Rebore

Cylinder Displacement

Rarely does one see Triumph 650 cylinders bored out more than 60 thousandths. It is said that the cylinder walls are in places quite thin, and overbores more than that are not reliable.

That being said, my Bonnie went around 12,000 miles on an overbore of 100 thousandths before she got a new set of cylinders at 86,000 miles.

The following table shows the effect of overboring on the displacement of the Triumph 650 engine.

Honing Cylinders

Before having your Triumph 650 cylinders honed, take the time to read the above posts by John Healy on the tried and true methods of getting a good re-bore and a good break-in.

After honing, cylinders need to be washed and scrubbed with a brush in hot water with detergent to remove ALL remaining abrasive material. It can't be over-emphasized how important this is. Wash them and wash again. And again. Foreign materials left behind may score the cylinders or block oil-ways, ruining the entire job with potentially catastrophic results.

When thoroughly clean, dry the cylinders with a clean cloth and then apply light coat of oil.

Tappet Guide Blocks

To remove or replace the tappet guide blocks it's essential to use the special drift: Service Tool 61-6008. It takes substantial blows with something like a little two-pound sledge to drive the blocks in. While a block is moving, it can be steered quite easily by twisting on the tool's hatch-marked handle.

On his DVD, Hancox says to line up the hole in the blocks with the locator screw hole in the cylinder block. For an amateur like myself that's not a sufficient guarantee that the tappet holes will end up exactly parallel to the camshaft. Instead I try to concentrate on the alignment of the tappet holes with the camshaft - if that is acheived the locator screw will line up for sure.

Tappets

The tappets ("lifters", "followers") ride up and down in the tappet block, operating the pushrods above them as they themselves rise and fall with the rotation of the camshaft lobes beneath them. Illustration of correct orientation of Triumph exhaust tappet
guide block

Illustration of correct orientation of Triumph exhaust tappet
guide block

Tappet Compatibility 1963-1970
Year	Tappets	Compatibility
1963-65	No oil feed to tappets Standard Radius (3/4) tappets	Tappets not forward compatible
1966	Oil feed to exhaust tappets R-Radius (1-1/8) inlet tappets	Tappets backward compatible, but not forward
1967-70	Oil feed to exhaust tappets R-Radius (1-1/8) inlet tappets	Tappets compatible with all tappet blocks

Reinstalling Cylinder Block Using a Piston Board

Using a piston board helps greatly in re-fitting a cylinder block over rings and pistons. A piston board is a platform that supports the pistons and helps keep them in place while the block is lowered onto them.

Piston boards don't need to be complicated, one made from an old kitchen cutting board has worked well for me.

Repro Cylinder Blocks

At 86,000 miles and already overbored to .100" it was time to replace the original cylinder block on my '69 T120R. The only 650 repros I could find in the US and Canada were all made by ARCO. If you're considering an ARCO 650cc cylinder block repro, be aware that esthetically they are different from originals (see photo here):

In addition, the casting behind and around the pushrod tubes are very rough - as in chunks of cast iron slag hanging off the fins. I returned the first one I received and the second one was only marginally better.

Later I learned that British suppliers offer different repros, possibly LF Harris. Faced with a similar choice today I would investigate other suppliers or even consider a used item.

Tightening Cylinder Base Bolts

It's not possible to get a torque wrench on the base nuts, but using a 6-inch 12-point 1/2" box wrench to tighten as hard as you can should approximate the proper torque of 35 lb.ft.. Note that the wrench needs to be quite a thin one to fit between the cylinders and certain ones of the nuts.

Painting Cylinder Block

Unquestionably, the best-looking and longest-lasting finish for the cylinder block is powder coat. For tips on other products and surface prep see link above.

Cylinder Head

Removing a Cylinder Head Stuck to Cylinder Barrels

Cylinder heads usually come off the barrels without too much difficulty, but they can occasionally be quite stubborn. If you've tried everything to no avail, check out this "Head Stuck to Cylinder" thread on Triumphrat.net. Several novel methods are presented and they are practically guaranteed to get your head unstuck.

Anneal and Install Head Gasket

Perfectly fine to reuse the copper head gasket as long as it is in good shape and properly prepared.

Begin by removing any burring that appears on the gasket. Burrs near the cylinders may create hot spots that can promote pre-ignition.

Next, always anneal a used head gasket before use. Some will even anneal new gaskets just to be sure. Annealing the gasket softens the copper and allows it to create a better seal between the head and the cylinders. The annealing process is simply heating the gasket cherry red and then plunging it into a container of water. If your heat source won't heat the entire gasket cherry red at the seme time it is ok to anneal the gasket one section at a time - just be sure every part of the gasket has been annealed.

Heating the gasket red hot often causes oxidation to form on the surface, particularly if it is heated multiple times. The oxidation probably doesn't affect the gasket's sealing properties, but as John Healy says, removing it makes for a more professional-looking job. Soaking the gasket in vinegar overnight will turn most of the oxidation into a brown "fluff" which can be rinsed off with water.

Apply grease or Permatex Copper Coat to both sides of the head gasket before installing. Using a sealing agent helps prevent oil leaks as well as compression leakage between cylinders.

Anti-Seize Compound

Although using anti-seize compound for head bolts and spark plugs is in some ways a good idea, it has two down sides. First of all, head bolt torque figures are given for dry threads, so they need to be revised downward when using anything on the threads.

Secondly, the anti-seize compound leaves behind considerable messy residue which must be thoroughly cleaned off during the next disassembly.

A cleanup method that works well is to fill the bolt holes with kerosene or brake cleaning fluid and then run the bolts in and out while using a rag to mop up solvent and crud as they run out past the threads. When the bolt bores are good and clean, clear them with compressed air.

Installing Cylinder Head & PRTs

Head Bolt Torque

The correct head bolt torques for unit construction 650s are 15 lb.ft. for the 5/16" bolt (#1), and 18 lb.ft. for the 3/8" bolts (#s 2-3-4-5-6-7-8).

The higher torques may look attractive to some, as they may find 15 lb.ft. and 18 lb.ft. too low. But it must be remembered that the torque will effectively rise as the cylinders and head heat up and expand. Over-torquing (beyond 15 lb.ft. and 18 lb.ft.) can result in indentations to the alloy head beneath head bolt washers. Extreme over-torquing can result in a cracked head. Cracked head, not good!

Torquing the Head-Bolts

Torque figures given are for dry threads. One recommendation is reduce by 20% when wet. So for example, if using anti-seize compound, one might use 15 lb.ft. instead of 18 lb.ft.. When I've used anti-seize compound I confess I've still used the 18 lb.ft. figure. Your call. Triumph 650 head bolts

The head bolts are tightened in the order 1-2-3-4-5-6-7-8-9 as shown in the accompanying illustration, and the final torque rating is reached by incremental steps. For example, tighten all the 18 lb.ft. torque bolts to 10 lb.ft. and then 14 lb.ft., and finally 18 lb.ft..

On his DVD, Hughie Hancox starts with bolt #1 and tightens each bolt one by one right to their final torque figure. I tried that method in 2006 and it worked ok, but I feel more comfortable using the incremental 'round robin' method.

The 1/4 inch rocker box bolts and the rocker box stud nuts are torqued to just 5 lb.ft.. Be careful. Install bolts and nuts at least finger tight before torquing head bolts. Doesn't hurt to tighten these fasteners incrementally among themselves and in conjunction with the head bolts. In the end the three nuts can be loosened slightly and re-tightened to obtain an identical torque.

Re-Torquing Head Bolts

After the first heat cycle(s) when the head has been removed and replaced, the head-bolts must be re-torqued to compensate for their looseness due to the "bedding-in" of the cylinder gasket, cylinder head, and bolts.

Because torque figures pertain to bolts when they are turning, it's not effective to just start tightening them. That would most likely result in over-torquing, which is never a good thing. So, the method is:

Note that the bolts don't actually loosen themselves, they loosen relatively, due to compression of the head gasket and stretch of the head bolts. Nevertheless, the question arises in many minds, were the bolts actually "loose" before re-torquing, and if so by how much? One way to find out is to mark one point of each head bolt and then make a corresponding mark on the head. After you re-torque you'll see whether it was necessary to re-tighten each bolt.

And as the "Duke of Oil" pointed out on Britbike.com, given their thread factor and how far the bolts turned to get back to spec it's possible to calculate how much the head gasket compressed and the head bolts stretched.

Recessed Valve Seats

Worn out valve seats or valve seats which have been ground too often or too much prevent valves from making proper contact with the head. This results in insufficient conduction away of heat and the possiblity of burned valves.

Here are some photos of the recessed valve seats in my 1969 T120R at a little over 88,000 miles.

Over-sized valves are sometimes posited as an easy fix, but not all agree it is a good one.

Replacing the valve seats is a difficult job as the originals are cast into the head. Very precision work to machine the new ones in tightly enough that they will never drop out of the head.

When the seats on Bonnie became seriously recessed I opted for a complete cylinder head restoration. The restoration included new valve seats, guides, valves, and springs. The boost to performance was nothing short of phenominal!

Rocker Boxes

Removing the Rocker Boxes

Next, remove the ignition coils and brackets and the torque stays and the rocker oil line domed nuts and copper washers (TS).

While it's not completely necessary to remove the ignition coils before removing the rocker boxes, it's advisable in order to completely clean the area above the engine before exposing internals. While they're off, polish the coils - up to 14% boost in performance!

After releasing spring tension, remove the 3 rocker box stud-nuts first. Then remove the outboard 1/4" rocker box bolts, and finally the two inside head bolts.

With the TS oil lines held free, extract the rocker boxes from the drive side (DS) by tipping and wiggling. Probably doesn't matter, but removing and installing I like to begin with the intake rocker box.

The Valve Train

Rocker Arms, Rocker Spindles, and Thackary Washers

The location of the Thackary washers on the rocker spindles ("shafts") has generated considerable discussion in the forums. Pity the poor Thackary, it's more a symptom of the controversy than the cause.

If you're curious about how Thackary washers got their name, Ian Peters, on "More To The Name", has an interesting story about that.

Over a period of several years, Triumph made modifications to both the rockers and the rocker spindles and also changed the location of the Thackary washers on the spindles. The changes were implemented unevenly across the models and years, and in some cases not at all. To top things off, Triumph failed to correctly document all the changes in parts books and workshop manuals.

Variations

In a nutshell, here are the variations of unit 650 Triumph valve train component:

Ok, I lied. There are really three styles of rocker spindles. There are the plain, un-grooved spindles (500 & 650s) , spindles with a spiral groove (T140), and spindles with a straight groove (Triples).

Unpacking the Triumph Rocker Box "Mystery"

The story begins with the Triumph rocker arms. The earlier style rocker arms, which went all the way back to the pre-units (RF Whatley) had a drilling to supply oil to their ball end. Whilst it provided very adequate lubrication, the drilling weakened the arms and they were known to break.

During the design of the Trident, which went into production in 1968, the then out-sourced design department at Umberslade Hall made several changes in the Trident's rocker boxes:

However, Triumph chose not to implement the new and improved grooved spindle design on any of their other models until the introduction of the 750 T140 in 1973, when it finally adopted the spiral grooved spindles for that new model. Meanwhile, the 500 and 650 spindles were never upgraded. (John Healy and John Healy)

Although the modifications were designed to work together and should have been adopted all together, Triumph initially adopted only the notched rocker shafts for the 650s (late 1968, beginning with DU79965). It has been suggested that even this adaptation was made rather grudgingly, and was more the case of having to use the parts sent to them by the new management.

Adoption of the newer washer arrangement for the 500s and 650s was made rather half-heartedly: while it gave notice of the swapped washer position (Thackary washer to the rocker box) in the 1969 Service Bulletin #25, most of the parts books and many of the service manuals were never changed. Also, machines continued to leave the factory with the original configuration - Thackary washers next to the rocker arms. According to John Healy, the Meriden factory persisted until the end in placing the Thackary spring washers against the rocker arms on the T140s, even after having adopted the grooved spindles! The change came about for the T140 only with the 1985-1988 production of the Harris Bonneville.

Some claim that the implementation of only two of the three modifications (rockers, washer position) without upgrading the rocker spindle actually resulted in less, not more lubrication than the older drilled rocker arms. Therefore, they conclude that there is simply no benefit in changing the position of the Thackary washers on 500s and 650s using either the original drilled rocker arms or the updated notched rocker arms unless they have a grooved rocker spindle (John Healy).

But others disagree, saying that in their original position Thackary washer tangs become fouled in the notches of upgraded rocker arms, thus reducing critical oil flow. They advocate for, minimally, moving the Thackarys outboard for all machines equipped with notched rocker arms.

Installing the Thackary washers against the rocker boxes makes the picky rocker box assembly an even pickier job due to the ID of the Thackary, the OD of the spindle step, and the way the Thackary interacts with the rocker box. T140V-Rich has a way with words, he describes it as " like putting a cat into a toilet".

I've tried assembling my 1969 T120R rocker boxes using the updated arrangement, but I never got that cat into the toilet. With 86,000 miles on the Bonnie, her original rocker box parts are still working just fine so I'm not worried.

Finally, some suggest that if Thackary washers are placed against the inside of the rocker box they will gouge the relatively soft alloy, but not according to (John Healy):

"The Thackeray, or spring, washer against the aluminum rocker box continued from the first to the last of the BSA and Triumph triples. It has never been a problem nor have they worn into the side of the rocker box!!"

There you have it in a nutshell. If you want to explore the iceberg in its entirety, see Mike James' excellent compendium of links (PDF) to BritBike.com Thackary washer, spindle, and rocker threads, including pertinent posts from John Healy on the entire subject and history of Triumph.

Rocker Spindle Washer Order Illustrated

Early Washer Order

Updated Washer Order

Assembling Rocker Arms, Spindles, & Washers

Both the Workshop Manual and Hanyes suggest using a 5/16" bolt ground to a taper at one end to line up the flat washers and Thackary washers before inserting the spindle. Seems to work well, with enough fiddling with it! (Beer break).

If a spindle doesn't go quite all the way in it's probably because the last washer (DS) is hanging up on the rocker spindle's shoulder. Don't force it! Play around with the washers and tap very, lightly on the end of the spindle with a plastic mallet. When everything is lined up it takes only a light tap.

Rocker Arm Spindle O-Rings

For what it's worth - Tool icon

special tool Z111, rocker spindle oil seal compressor, is available. I've never found it effective or helpful.

Pushrod Tubes (PRTs)

Pushrod Tube Styles

Between 1965 and 1972 three different pushrod tubes, each with its own type of seal were used on "B" range 650s. The earlier PRT (70-6000) has a different length than both the later 70-9349 and 71-2575 and as well so they are incompatible with the later cylinder heads and tappet guide blocks.

On the other hand, while the later 70-9349 (fabricated) and 71-2575 (one-piece) PRTs used different seal methods, their lengths were the same, they used the same tappet guide blocks and compatible cylinder heads, so they are interchangeable during those years.

Summary of Heads, PRTs, and Guide Blocks 1967 - 1972
Part	1967 - 1968	1969 - 1970	1971 - 1972
Pushrod tube	70-6000	70-9349	71-2575
Cylinder head	70-7031	70-9418	71-2354
Tappet guide blocks	70-4676 / 70-5861	70-9352 / 70-9353	70-9352 / 70-9353

Pushrod Tube O-Rings

Oil leaks from the pushrod tubes (PRT's) have been a perennial problem for many Triumph owners.

In 1969 Triumph replaced the rubber sealing washers used by earlier models at the top and bottom of the PRTs with o-rings. The new o-rings fit into newly designed PRTs (70-9349) and inlet and exhaust tappet guide blocks (70-9352 / 70-9353). O-rings at the top of the PRTs stood up poorly to the high temperatures there so beginning in 1971 Triumph substituted a different upper o-ring. The new high temperature red 71-1283 o-rings were somewhat a disaster. I used them twice and both times they quickly crumbled to pieces. Later, the 71-1283 o-ring became available in Viton and the Viton units proved to be far more durable.

Meanwhile, in 1971 Triumph introduced a new PRT, the 71-2575. The new PRT continued using o-rings top and bottom, but added a compression seal at the bottom, along with a metal sleeve (aka the "wedding band") to prevent the new seal from squeezing out when compressed by bolting down the cylinder head.

Pushrod Tube Sealing Part Changes 1969 - 1971
Part/Year	#7 ('69)	'70 USA	'71 USA	'72 USA
Bottom o-ring	70-7310	70-7310	70-7310	70-7310
Top o-ring	70-7310	70-7310	71-1283	71-1283
PRT (pushrod tube)	70-9349	70-9349	71-2575	71-2575
Sealing ring	-	-	70-4752	70-4752
"Wedding Band" sleeve	-	-	71-1707	71-1707

Pushrod Tube Sealing Ring & Wedding Band

In 1971 Triumph added another oil seal in addition to the o-rings found on the 1969-1970 models. The new "sealing ring" (70-4752) sits between the PRTs and the tappet guide blocks and has a square-section to improve sealing. The "wedding band" metal sleeve fits over the sealing ring and keeps it from being squeezed out of place by the pressure of the cylinder head being tightened down on the PRTs.

The square-sectioned sealing rings are commonly, but not always, white silicon. I've had black, sponge-like seals and they worked fine. These seals come in different thicknesses to enable adjustment of "the crush". (See section below).

Goldilocks Pushrod Tubes, and "Crush"

'Crush' refers to the amount of compression of the PRT seals and o-rings when the head bolts are tightened. Too little crush means the seals may be compressed insufficiently to prevent oil leaks. Too much crush can distort the seals and create leaks. But worse yet, too much crush can cause the alloy cylinder head to warp when the outside head bolts are tightened even as the center of the head is shimmed up by too much crush.

When the cylinder head is sitting freely (loose bolts) on top of the cylinder barrels with head gasket and PRT seals and o-rings in place, there should be between .020 and .030 in. gap between the cylinder head and the head gasket. This gap will achieve the just right Goldilocks crush. Too much gap means too much crush, too little gap means little crush.

The gap can be adjusted by substituting different thicknesses of sealing rings. A thicker sealing ring holds the PRTs and the head higher, increasing the gap and the crush, while thinner seals reduce the gap giving less crush. In extreme cases when a cylinder head has been skimmed adjustment may also include a thicker head gasket.

Install head with bolts 6,7,8,and 9 fitted evenly and lightly enough that the bottom seals and top o-rings are not being compressed. Then check for a suitable gap that is even all the way around.

Installing Pushrod Tubes & Cylinder Head

Although one of Bonnie's pushrod tubes seats very tightly at the bottom and the other is relatively loose, they both seem to seal well to the tappet block once the head is bolted down and the sealing ring squashes out to the wedding ring.

Be sure to oil the top and bottom o-rings before assembly (sharp edges ahead). It's also ok and good to grease the top o-rings to help hold in place as well as lubricate.

In 2016, I used 'Right Stuff' on the top o-rings during first assembly. Upon disassembly 450 miles later, I picked the Right Stuff 'slime' out of the o-ring groove. No more 'Right Stuff' for me. Back to oil and grease.

When installing the head, it may go better to maneuver it into place from the rear, as opposed to from one side or the other.

Slight in & out adjustments (punch and ball peen) to the tabs at the top of the PRTs can sometimes ease installation or removal of the PRTs. Just be sure the tabs don't foul the pushrods when they are installed.

PRT O-Ring & Seal Dimensions

When adjusting for proper sealing ring crush, the following dimensions could be helpful.

Common Dimensions for Estimating "Crush"
Component	Height
Cylinder Head	2.755" John Healy 2.785" (Internet forum)
Head Gaskets	.045-.050 .080 .100
Round o-rings	70-7310 (Buna-n) / 71-1283 (Viton) ID=.987"/Nom 1" CS=.103"/Nom 3/32" OD=1.193"/Nom 1 3/16" Dash#120
Square-sectioned sealing rings	70-3547 Thick= .093"/nominal 3/32" (.095 Raber's) 70-4752 Thick= .125"/nominal 1/8") (.125 Raber's) 70-1496 Thick=.1875"/nominal 3/16" (.177 Raber's)
Pushrod Tubes	70-9349/71-2575 4.867"

Rocker Box Gaskets

Types of gaskets for the rocker boxes include plain paper, wire-reinforced, and Covseals.

I used wire-reinforced gaskets many times because they were supposed to be good. Not in my experience: all became hard and brittle and more times than not they leaked seriously. I switched to plain paper gaskets from MAPCycle and had much better luck. Still later I tried Covseals and they became my go-to r-b gasket. Covseals are a sandwich of composite material with a metal core.

Posters in the BritBike.com thread just above say Covseals applied dry as per included instructions can work fine, but using a sealant like Hylomar Blue is the dependable way to get oil-tight rocker box joints.

Regardless of how you install them, expect removal of Covseals to be a job. Or, maybe try out JubeePrince's suggestion in the same thread above.

Replacing Push Rods and Rocker Boxes

I label the pushrods with a marker when I remove them & replace in their same position. If I remember, else not. As I replace the pushrods I examine them and, ideally, make note of anything special, such as wear to the cups.

Rocker Box Gasket Modification

When I tried using lightweight pushrods it was necessary to modify the rocker box gaskets to accommodate their larger diameter. After modification the gaskets no longer served to guide the pushrods to the rockers when fitting the rocker boxes, so I made a template to guide the pushrods, split it in two, taped it back together for assembly, and removed in two pieces when the rods were placed.

Replacing Rocker Oil Feed Pipe

Always anneal the four copper washers before replacing them, even if you seal them:

Replacing Engine Torque Stays

Valves

Replacing Valves in Head

Install valves, springs, and retainers as shown in the figure at right. Lubricate valve stem before inserting into valve guide. Use a valve spring compressor and apply a small amount of thick grease the split collets to help hold the first one in place while inserting the second one. Cover with a rag or take other precautions to prevent collets from flying off to parts unknown should they not be engaged by the top cup when spring tension is released.

Adjusting Valve/Rocker Clearance

Looking at the valve clearance specs for the T120 and for the T140 it may appear as though there is an error, but that is not the case. What accounts for the difference? According to Mr. Pete, "Different cams, with different ramps. No quietening ramp at all on the 3134 cam in the T120."

Valve Clearance Values for Triumph T120 and T140
	Inlet	Exhaust
T120	0.002	0.004
T140	0.008	0.006

It's universally acknowledged that a wee bit too much valve clearance is better than not enough. This is especially true for the exhaust valves. If exhaust valves are prevented from closing, a lack of contact with the valve seats means they are unable to dissipate their heat and the result is burned valves. On the other hand, excessive clearance cause the rockers to 'hammer' the valve stem tips, damaging, and potentially ruining them.

When the rocker boxes or the rocker boxes and cylinder head are replaced with new gaskets (or after head bolts are re-torqued), it's important to re-set valve clearances after a brief break-in of the new gaskets.

The break-in compresses the base and rocker box gaskets as well as the PRT seals, and valve clearance becomes significantly reduced or, commonly, reduced to nil. When that happens engine temperature soars (smokin' hot!), there's a loss of compression and engine power, and then the valves burn.

After a top end re-assembly with new gaskets and a generous preliminary valve clearance adjustment, my first ride is about three miles, one-and-a-half out and one-and-a-half back. Much more than that and she's smokin' hot upon return. Gaskets may subsequently compress sightly after the "milder" break-in, but generally to an insignificant degree.

Sound can be a useful guide to setting valve rocker clearance (see 'Adjustment by sound and feel', just below), as well as when evaluating correctness of settings with the engine running.

If carburettors are off it's a perfect time to adjust valve clearance, but adjustment is usually performed after simply removing the gas tank and air filters.

Valve Adjustment Tools

The stock Triumph adjustment pins have square heads which make adjustment quite vague. If you're using the square-headed adjustment pins there is a two-piece valve adjuster tool available. In theory this tool should make adjustment a snap because it allows control of adjustment with thumb and finger while simultaneously tightening or loosening the locking nut. In practice, the fit between the adjustor and the square pin is too sloppy for effective control at these dimensions.

One adjustment technique is to use a ring wrench on the lock nut and a screwdriver in a slotted adjusting pin and use the interplay between tightening and loosening the wrench and the screwdriver to "steer" the adjuster ever so slightly into position for the correct clearance.

Coarse adjustment by position

Valve clearances should be set to .004" for exhaust and .002" for the intakes. A common method of obtaining 'ballpark' settings is to run the adjustors in until they just contact the valve stems by feel, and then back them off 1/8 of a turn for exhaust, and 1/16 turn for intake.

Adjustment by sound and feel

Another common adjustment method is to grasp the rockers with thumb and index finger and rock them up and down:

Positioning Valves for Clearance Adjustment

The WS Manual Method of Positioning and Adjusting Valves

In order to adjust a valve's clearance, the valve must be fully closed. The Workshop Manual method is:

So, to adjust the TS intake valve as shown in Step 1 above, close it by opening the DS intake valve (rocker adjuster down):

Lunmad's Method of Positioning and Adjusting Valves

Combined Method of Positioning and Adjusting Valves

If you examine the WS Manual and Lunmad methods carefully you'll see that the two methods can be combined into one.

Adjustment after Re-torquing

When the cylinder head has been removed and replaced, valve clearance needs to be re-adjusted several times due to gasket 'crush'. Adjust:

Engine Compression

Compression Test

Testing engine compression is a quick and easy way to determine an engine's general health with regards to valves, rings, and cylinders.

I've always used these five steps, but for better, more accurate results check out Don's method in the post just above.

If valves are suspected, check to ensure there is adequate valve clearance to prevent valves from closing fully.

Sudden Loss of Compression

Once, after sitting unused (very rare) for ten days, the Bonnie seemed to give up all compression after the first kick. TR7RVMan on BritBike.com correctly diagnosed the problem and offered a solution which consisted of pouring a couple of tablespoons of oil down the plug holes, kicking over the engine several times with the plugs out to remove excess oil, replacing the plugs, and starting as usual. The method worked perfectly and normal compression was restored as soon as the bike started.

Ignition Timing

Setting Ignition Timing with Points

Static and Dynamic Timing Procedures

For clearly illustrated instructions on setting ignition timing with points see "Hermit's Illustrated Ignition Timing with Points". Also be sure to read TR&RVMan's superb posts on ignition timing using the 4CA and 6CA breaker points assemblies - links just above in Resources.

Determining When Points Open for Static Timing

Dynamic Timing Tips

Setting Ignition Timing with Pazon

Static Timing

Use a flywheel locator tool (OR timing pointer and rotor timing mark if the one on your rotor points to 38 degrees BTDC and not TDC) to locate 38 deg advance.

Dynamic Timing

Primary Cover Timing Pointer

The timing pointer in the primary chaincase cover on later model 650s is basically a short nail - a flat head on one end a pointer on the other. It is a press fit in the primary cover.

Replacing rotor cover after timing

If the cover is installed on the chaincase before screws are inserted, mating the first screw to the threads in chaincase can be annoying. Easier to find the hole by inserting the top screw in the cover and fitting both together dangling from a Phillips screwdriver.

Removing magnetic rotor center

Spark Plugs

Used NGK for quite a while, but have returned to using Champion N3C (new Champion designation 801).

Interpreting NGK plug designations:
B= 14mm plug thread
7 = Temperature range
E = 19mm plug thread reach
S = Standard super copper core electrode

The higher the NGK number, the colder the plug
The lower the Champion number, the colder the plug

The Exhaust System

Removing Exhaust System

If you don't have a crossover pipe and you don't fit the muffler strap, you can remove the exhaust pipes and mufflers as a unit: remove or loosen the exhaust pipe clamps (7/16"), the exhaust pipe engine bracket (Phillips screws and 7/16" nuts), and the muffler hanger bracket nuts/bolts (1/2").

The nuts holding the chrome exhaust brackets to the engine are 5/16" BS, but it's not necessary to remove them.

When removing and replacing the exhaust pipes on the exhaust pipe adaptors, I find it's ok to hit them with a plastic mallet using a thick, folded rag as padding.

Sealing Exhaust Leaks

I have Bonnie's original headers with crossover pipe in inventory, but I replaced them (several times - I've seen the gravel and the damage done) with separated headers.

Not running headers with a crossover, I don't have the problem of sealing exhaust leaks there, but apparently this can be a problem, especially with reproduction parts. Don's method takes the guesswork out of centering the crossover pipe to cover the slots in the stubs on the headers, this and other good tips. See link above.

Loose Baffles

Loose lips sink ships and loose baffles rattle. A loose baffle can be re-welded, but it requires drilling an access hole on the inside of the muffler where the baffle is loose. Afterwards, the hole gets welded shut. Makes an effective and virtually invisible repair.

It has been suggested that loose muffler baffles could be a result of not installing the muffler brace ((70-5676, Ref.27 Fig.15 Page 41 #7). Probably some validity to this. I wonder how many people actually fit this part?

The Transmission

Primary Chaincase

The primary chaincase houses the transmission, which consists of the engine sprocket, the primary chain, and the clutch assembly. The transmission's job is to transfer energy from the engine sprocket to the gearbox mainshaft, the gear cluster, and subsequently to the gearbox sprocket and rear wheel.

Primary Chaincase Lubrication

Primary Chaincase Cover and Gasket

If you're having difficulty removing the primary chaincase cover, see the BritBike.com post "Primary Case Removal" - resource link just above.

The Britbike.com thread "Primary Chaincase Gasket" (resource link just above) will probably satisfy all your needs concerning the subject - Five-Star thread.

Primary Chaincase Inner Cover Plate, AKA "Trap Door"

The primary chaincase inner cover plate (70-7037, Ref.7 Figure 11 RPC#7) sits behind the clutch on the rear of the primary chaincase. It's held in place by six machine screws and sealed by a gasket.

The center hole in the cover plate has an oil seal through which the mainshaft passes on its way through the gearbox sprocket and into the gearbox.

The Primary Chain

Check Primary Chain Wear

Check Primary Chain Tension

Excessive tightness of the primary chain can damage the DS crankshaft bearing, the chain tension slipper, clutch components, and/or the gearbox mainshaft and its bearing. Conversely, too much slack can give rise to some bad-assed noises from the primary chaincase, not to mention damage to the stator or the primary case itself due to rubbing.

In one place the WS Manual specifies 1/2" total up-and-down slack, but a different section says 3/8". Since a chain's slack often varies from one point to another in its rotation, the two specs might be taken together as the acceptable range. Always check chain slack all around the chain, marking tight and loose spots with chalk before adjusting as necessary.

Adjust Primary Chain Tension

In order to adjust the primary chain tension, the oil must be drained from the primary chaincase, so it's only logical to check the tension at each oil change and adjust if necessary.

What I've found is that when chain tension is correct, running the adjuster in one turn will make it too tight and running it out one turn will make it too loose. So when adjusting the tension I look for the sweet spot that way.

Dismantle the Transmission

The clutch assembly, engine sprocket, and primary chain are removed simultaneously as one after slacking the chain and removing the stator and rotor.

Step-by_Step Procedure

Inspecting Transmission Components

Clutch Pack Thickness

According to Don on TriumphRat.Net, a genuine Triumph clutch stack will measure 'very close' to 1.400", while an Aerco 7 plate clutch with all new steels will measure 1.380".

Clutch

Shock Absorber Rubbers

Clutch Hub & Thrust Washer Compatibility

1963-69 Triumph 650s came with the 57-1734 clutch hub and its 57-1735 thrust washer. That duo was upgraded beginning in 1970 to clutch hub 57-3929 and thrust washer 57-3931. The newer combo is a recommended upgrade for older machines.

You can verify whether a thrust washer is compatible with a clutch hub - the thrust washer's inside diameter should fit the matching recess in the hub.

Both thrust washers (57-1735 and 57-3931) are, or were, available in different materials:

For thrust washers with one side copper and one side steel, place the copper side towards the clutch basket.

The spec given by the manual for thrust washer thickness is .052/.054". Some vendors supply thicker washers, but there are reports that too-thick a washer can make the clutch pack lock up when the clutch center locking nut is tightened.

Assemble the Transmission

Assemble Clutch Hub, Rollers, and Clutch Center

Install Duplex & Engine Sprockets & Primary Chain

The duplex chain sprocket, with its clutch hub, rollers, and clutch center, is installed simultaneously with the engine sprocket and primary chain. If you can do this while juggling several wrenches you could be on the Ed Sullivan Show.

Triumph Clutch Hub and Thrust Washer Compatibility
Years	Hub	Thrust Washer	ID	OD
1963-1969	57-1734	57-1735	1.84" (1.88)	2.62"
1970-	57-3929	57-3931	2.035" (2.02)	2.62"
ID in parenthesis from Klempf's British Parts

Clutch Hub & Thrust Washer Compatibility
Component	Earlier	Upgrade
Clutch Hub	57-1734	57-3929
Thurst Washer	57-1735	57-3931

Naturally the DS crankshaft oil seal must be installed before installing the engine sprocket. Click here for details on installing the oil seal,

Adjust the Pressure Plate

Three adjustors permit adjustment of the pressure plate until it lifts and falls evenly and compresses the clutch plates evenly all around.

After initially setting the adjuster nuts flush with the ends of the adjuster screws, use a pressure plate spring adjustment tool to adjust the three pressure plate spring adjustment nuts to eliminate wobble of the pressure plate as it turns.

To check for wobble, pull in the clutch lever to raise the pressure plate and then turn the clutch using the kickstarter. Observe the outside edge of the pressure plate for wobble as it goes around and use the spring adjustors to compensate for unevenness.

Wobble can be gauged by eye, but a pointer is a great help and can be as simple as a piece of coat hanger wire and some duct tape.

After adjustment, make final check is to see that the pressure plate lifts evenly all around when pulling in the clutch lever.

Properly adjusted, clutch spring tension should be a happy medium between too loose (clutch will slip) and too tight (excessive hand pressure required to operate the clutch and possibility of damage to the clutch rod). If the coils become bound or the spring tension otherwise too high, loosen the three adjustors by small, equal amounts at a time until spring tension is eased and then re-check wobble.

Adjust the Clutch Operating Mechanism & Clutch Cable

Adjustment Tips & Techniques

The procedure is pretty straight forward, but there are a couple of tips and techniques for best results.

Clutch Operating Mechanism (Ball & Ramp)

Clutch Problems

Clutch Operating Mechanism Pops or Clicks

If a popping or clicking noise occurs when pulling in the clutch lever it means the 3-ball clutch operating mechanism in the outer gearbox cover is out of its adjustment range. This occurs if the clutch rod is under-adjusted (too much slack) and the cable adjustment is over-adjusted in compensation. That combination of poor adjustment advances the static position of the clutch operating mechanism until normal operation of the clutch lever/cable forces the mechanism past its designed operating range. When that happens the steel balls click and pop as they pass the ends of their ramps.

All that's necessary to correct the condition is to properly adjust the clutch operating rod and the clutch cable as described above.

Clutch Drags & Neutral Hard to Get

Clutch Pull Very Stiff

Kickstart Lever Won't Turn Engine/Gearbox Won't Engage with Engine

Gears Crunch When Selecting First from Neutral

You might have heard it said that there's a Triumph part number for the crunching noise a Triumph makes when first gear is selected from neutral at a standstill. All Triumphs make the noise some of the time, and some Triumphs make the noise all of the time, but with perseverance the problem can be eliminated, or at least greatly attenuated.

Although the culprit is usually clutch-related, other causes, including gear oil, are possible. See

Causes

Techniques for Reducing the "Crunch"

The Gearbox

Gearbox Lubrication

Gearbox Problems

Jumping out of Gear

Jumping out of gear is not an uncommon problem with the 650 (and 500) gearboxes. My 1969 T120R suffered from the problem for over two years before I found the fix.

Jumping out of gear is often ascribed to gears with worn dogs, but the dogs of my bike's gear set seemed just fine.

Eventually I began thinking that a defect somewhere in the gear changing mechanism might be preventing the gears from being fully engaged to begin with. That idea led to the gear shift quadrant (not to be confused with the inner quadrant - see this Illustration).

Holding the gearbox outer cover gently in a vise with wooden jaws, I affixed a degree wheel to the end of the gear shift quadrant and rigged up a wire pointer set to zero degrees with the gear shift lever in its center position. I then deflected the shifting lever in both directions and recorded the degree readings from the pointer and wheel.

What I discovered was that the gear shift quadrant traveled significantly less when down-shifting than when up-shifting. Were gears sometimes incompletely engaged following down shifts and thereafter prone to "jumping out of gear"?

With a new gear shift quadrant installed in the outer cover I fitted the degree wheel and compared its up and down shift deflections. Barely half a degree difference. Upshift 19 degrees, and downshift 19-1/2 degrees.

Less than one-half a degree doesn't sound like a lot, but when I measured the actual downshift travel of the old and new quadrants I found the replacement quadrant traveled around 3/32" further than the original.

The new gear shift quadrant fixed the problem one-hundred percent. The problem has never reoccurred during the intervening years and tens of thousands of miles.

So the problem turned out to be that the gearshift quadrant's throw was insufficient to dependably push the all the components of the shifting mechanism fully into position. That created an unstable condition prone to jumping out of gear when exposed to stresses and shocks.

As shown by the linked illustration above, the shifting mechanism components consist of the gear shift quadrant and its pawls and springs, the inner quadrant, the shifting forks, the camplate, and the index plunger with its spring.

In Bonnie's case, the gearshift quadrant's travel was too short, but it's also possible for things to get pushed a bit too far, again setting up an unstable condition prone to disengaging under stress.

Outer Gearbox Cover

Some say an outer gearbox cover gasket can cure certain gearbox problems. Possibly, but forum concensus leans to probably not. I tried one once. No effect in that case. Only time i ever used a gasket. Bonnie didn't come with one and sealant is all that's generally necessary. Hylomar Blue is excellent and just made for this application.

Kickstart Lever Tapered Pin

Removing the tapered pin holding the kickstart lever in place is not always so easy. The pin gets bent out of shape by the force of repeated kickstarts, effectively jamming itself in the bore. It sometimes helps to jam the kickstart lever forward using a plastic mallet and then whack the pin smartly against the nut threaded flush.

As noted in the Britbike.com thread above, some kickstart pins are made of harder material than others and they tend to distort less than softer ones.

Removing Outer Gearbox Cover

Dismantling and Reassembling the Gearchange Mechanism

Kickstart Mechanism

Now pay attention because there will be a quiz later: the kickstarter nut at the end of the mainshaft is one of the four places to use Loctite on a Triumph.

Inside the gearbox, the kickstarter shaft rotates a quadrant which engages a pinion gear on the mainshaft. The pinion gear turns freely on the mainshaft, but a small spring permits it to part-time engage a ratchet which is splined to the mainshaft and therefore turns it

On the transmission side, the mainshaft connects, through clutch center and clutch plates, to the duplex sprocket, duplex chain, and engine sprocket on the DS end of the engine's crankshaft.

While the clutch lever is in and clutch plates disengaged, pumping the kickstarter lever is to no avail: the clutch center and the steel plates turn, but rotation ends there due to lack of engagement with the friction plates. This action, "freeing the clutch", is performed at the beginning of each riding day as a way to break the "stiction" between the steel plates and the friction plates.

However, supposing the engine doesn't turn over when the clutch lever is out and the kickstarter is depressed? Obviously there's a problem, but where? As we just saw, some parts to the kickstart mechanism are in the gearbox and others are in the primary chaincase so there's only a 50/50 chance of finding the problem by randomly removing one of the covers.

Replacing Outer Gearbox Cover

Inner Gearbox Cover

Removing the Inner Cover & Dismantling the Gearbox

Inspecting the Gearbox Components

Layshaft End Play

The workshop manual doesn't give a spec, but the consensus on forums is that layshaft end play is not so critical as long as there is enough to prevent binding. An end play of .005" is frequently suggested, but anything up to .030" could work o-k.

Gearbox Sprocket

Replacing the gearbox sprocket requires dismantling and reassembling the entire transmission. Before installing a used sprocket, pay close attention to wear and quality.

Sprocket wear and chain wear are contagious. Wear on any component in the final drive increases wear to the others as well. Proper chain maintenance (clean, lube, adjust) will add significantly to the life of a gearbox sprocket, thereby postponing its vexatious replacement.

1969 T120R Gear Cluster Illustrations

Gears, Shafts, Bearings, & Bushes('69 T120R)

Gearbox Bearings

Removing and replacing the gearbox bearings requires heating their casings. A non-contact infrared thermometer takes the guesswork out of attaining an even 200F/100C temperature. In the absense of such an instrument you can resort to the sizzling spit method.

Bearing Identification

The mainshaft is supported by two ball journal bearings, while the layshaft runs in a needle roller bearing at either end.

Removing Mainshaft Bearings

Removing DS Mainshaft Bearing (57-0448)

Removing TS Mainshaft Bearing (60-3552)

Replacing Mainshaft Bearings

Replacing DS Mainshaft Bearing (57-0448)

Replacing TS Mainshaft Bearing (60-3552)

Removing Layshaft Bearings

Removing DS Layshaft Bearing (57-1606)

Removing TS Layshaft Bearing (57-1614)

Replacing Layshaft Bearings

Replacing DS Layshaft bearing (57-1606)

The first two times I replaced the layshaft needle bearings I heated them and used a drift with a heavy hammer. The third time I enlisted the help of a machinist to press them in. Using the plywood Photo icon

engine base I made and his 50-ton hydraulic press made it super easy.

The specially shouldered drift I had fabricated to install the layshaft needle bearing 57-1606 was supposed to ensure the bearing's correct protrusion (.073-.078") above the gearbox casing, but it turned out to have not been made correctly. Nevertheless, the correct installation was acheived by going slowly a little bit at a time.

I marked the position of the thrust washer locating peg on the casing with a permanent marker to make it easier to align the matching hole in the thrust washer while installing the mainshaft.

Replacing TS Layshaft Bearing (57-1614)

Replacing High Gear & Gearbox Sprocket

The mainshaft high gear and gearbox sprocket must be installed before assembly of the gearbox.

Note that gearbox oil leaking from around the sprocket may be a sign that the DS mainshaft bearing and/or the mainshaft high gear are worn, with the resulting excess play defeating the mainshaft oil seal.

Gear Ratios & Tooth Count: 4/5-Speeds

The following table summarizes the gear ratios and tooth count for Triumph 4/5-speed gearboxes.

Installing Gear Cluster

I've used several methods to assemble and install the gear cluster and in my experience Hughie Hancox's method is hands down the easiest, surest, and fastest way to do the job.

However you assemble, don't forget to seal the shifter fork shaft and the gearbox sprocket if you expect to not have oil leaks. Seal the shifter fork shaft because its drilling goes all the way through the casing. Permatex and Hylomar have both worked well for me. And keep in mind that after the gear box sprocket is installed, the shifter fork shaft drilling cannot be reached.

The layshaft thrust washers deserve special attention. Their grooved sides face the gears, not the cases, and they should fit well on their locating pegs. To prevent them from falling off the pegs during assembly, put a smear of heavy, sticky grease on the sides facing the cases to stick them there. Avoid greasing the sides facing the gears, that could result in the washers being pulled off their pegs.

During my first gearbox adventure I ended up reinstalling the gear cluster five times, and the transmission twice. The first time I put the cluster in it took just under two hours. The fifth time it took less than three minutes.

At that time I tried three different ways to install the gear cluster. Of the three, I found the WS Manual method (see Method 3, below) of installing the gear cluster as a unit to be the easiest. The only way I deviated from the WS Manual was to index the quadrant and camplate in 1st gear instead of using neutral between 2nd and 3rd as shown by the WS Manual (see "Indexing the Camplate & Quadrant " below.

The next time I reassembled the gears I used the method shown by Hughie Hancox on his DVD, in which he puts the gears in place one at a time. I made several dry runs and could hardly believe how easy this method is.

The one thing I did differently from Hancox was that I did not pre-install the mainshaft and kickstarter assembly in the inner cover the way he does in his video. Instead I inserted the mainshaft by itself before putting on the inner cover and then the kickstarter parts. Next time I'll be inclined to pre-assemble the way Hancox did simply because that way the kickstarter nut can be tightened (45lbs) while the shaft is held in a vise.

Four Variations on Gear Cluster Installation

Method 1: Juggling

Method 2: Juggling

Method 3: Workshop Manual Variation

When I re-assembled the gears for the fourth and final time I used the method shown in the WS Manual, i.e. introducing both mainshaft and layshaft with all their parts and the shifting arms as a unit. With enough patience it does work. While the WS Manual shows the mechanic inserting the entire assembly without the rod upon which the shifter arms travel, I achieved assembly with the rod inserted through both shifting arms.

When inserting the cluster, first tip the cluster clockwise a bit to get the roller on the mainshaft gear shifter into the camplate. Then, going in further, tip the cluster counter-clockwise to get the layshaft gear shifter's roller into the camplate. The last time I did it the whole thing took less than three minutes.

Method 4: Hughie Hancox

I saved the best for last! Hancox assembles the layshaft, layshaft gears, and mainshaft gears in situ before inserting the mainshaft, already installed in the inner cover, through the mainshaft gears.

Nearly everyone who tries this method agrees that it is the easiest and fastest of all. For photo-illustrated step-by-step instructions, follow this link:

Thrust Washer Locating Pegs

The thrust washers at either end of the layshaft are held stationary by hardened steel locator pegs in the casing that match holes in the thrust washers. Occaisionally a thrust washer will come off its locator peg and that usually results in either the peg or the washer getting ground down. Here are some descriptions of the problem with details on replacing damaged pegs.

When the Bonnie's locating peg for the DS thrust washer became damaged, I took the engine to the best machinist around and he fabricated a jig which he used to drill a new hole for a replacement peg.

The best way to avoid the washers falling off their locating pegs during assembly is to apply some thick, sticky grease to the backsides to stick them to the case. The plain sides of the washers face the case while the grooved sides face the gears. Keep the grooved sides clean and grease/oil free so they don't stick to the gears and pull the washers off the pegs.

Indexing the Camplate & Quadrant

If the inner cover of your gearbox has been removed, the gearshift camplate and the inner quadrant must be reindexed during reassembly.

Indexing the gearbox camplate and quadrant is a procedure that insures that the teeth of the gearshift camplate and the teeth of the inner quadrant are correctly positioned relative to each other as the inner gearbox cover is pushed on.

Indexing the camplate and the quadrant correctly is essential to proper gear shifting operations. Being one or more teeth off in either direction will result in faulty gear shifting and/or one or more gears being inoperative.

Hermit's article "How to Index the Triumph 650 4-Speed Gearbox" includes all the info you need to successfully index your gearbox - complete instructions and clear, detailed photos for every step.

Positioning the Camplate for Indexing

Indexing can be accomplished with the camplate set in any one of three positions: 1st gear or 4th gear (both shown below), or in neutral between 2nd & 3rd (not shown below, but easily interpolated from 2nd and 3rd gear positions as straight up and down).

Positioning the Quadrant for Indexing

Note on Replacing Gearbox Inner Cover

If an oil filter head is installed on the down tube, be sure to install the lower forward engine mounting bolt through the back of the inner cover before putting the cover in place. Once the inner cover is in place, the filter mounting bracket prevents inserting the bolt from the back. If the bolt is installed head out, it interferes with the oil lines on the inside.

The Fuel System

Gas tank

When installing the gas tank, tighten the rear mount first. If the front nuts are started first it makes the gas tank lift up in back. This may be why so many Triumphs have stripped threads in the rear frame mount. They were stripped on three out of three of my Bonnevilles - with two of them coming that way to me. Now I use a large tie-wrap over the tank's rear mounting tab (bolt and all rubber parts in place) and through the sidecar mounting hole.

Not all Bonnies are the same, but on mine I tighten the front mounting nuts incrementally from side to side to make sure I end up with an equal spacing between the frame and either side of the tank. We don't want to crush cables or the headling wiring harness.

Neither leaving the gas tank full of fuel over the winter or emptying it is the best way to prevent rust in you tank. See the Resources link "How to protect the petrol tank" above for a discussion of what guys do with their tanks in the winter.

Gas Line

After reading through this WWW icon

TriumphRat fuel line thread I decided, for safety reasons, to switch from classic look reinforced plastic lines to rubber hose. Not only are plastic lines more prone to leaking, in case of a fire they will melt and add gas to the flames.

Gas Taps

Installing/Removing

The brass gas tap fuel line connectors shouldn't be so tight that they can can't be loosened by a few light raps with two or three fingers on a wrench. Avoiding over-tightening prevents the gas tap from turning and possibly breaking the seal to the tank.

Sealing Leaks

Rebuilding and Lubricating Originals

Carburettors

Random Notes

Carburettor to Adaptor O-Rings

While the thin Amal o-ring was used most often in conjunction with an insulating block (E2968) and a joint washer (NA43A), the thicker 70-9711l o-ring is used solo, without joint washer or insulating block. The thin o-ring relies on the insulating block to reduce heat transfer between the engine and the carburetter, while the thick ring reduces heat transfer by creating an air gap between the engine and the carb.

In addition to being a more efficient heat insulator, the thicker 70-9711 o-ring reduces the chance of warping the carburetter flanges caused by uneven or over-torquing the carburetter's mounting bolts.

A small dab of grease helps keep the o-rings in place while offering the carburetter to the mounting studs. Don't use too much grease or the o-ring will migrate as you tighten down the flange.

Next it's finger yoga putting on the rubber insulating rings, cupped washers, and lock nuts, all the while holding the carb ever so slightly off the adapter so the nuts will clear the casting around the ticklers as they are started. Once the self-locking nuts are started, tighten them evenly from side-to-side until there is a .040" to .060" gap between the carb flanges and the adapters.

Amal Concentric 930 Cross-Section

Amal Concentric Carburettor Parts

Amal Concentric Carburettor Setup Summary

Amal Concentric Carburettor Modifications, Mid-1969
	Needles	Needle Jet	Jet Holder
Pre-Mid 1969	2-9/32" long One ring	11/16" long	3/4" long
Post Mid-1969	2-21/32" long Two rings	13/16" long Cross-drilled	7/8" long

Amal Concentric Carburettor Setup for 1969 Triumph T120R
	Manual	Bonnie
Main jet size	220	190
Needle position Up = richer	2	2 (middle)
Needle jet size	.106	.106
Cutaway	3	3
Idle speed adjustment screw		nom 1 1/2 out
Idle air adjustment (out for lean, in for rich)	2 1/4 - 2 1/2

Choke Assembly

If your Amals are fitted with chokes and you decide to remove them, Amal makes a blanking screw: Amal part number 4/137. Otherwise the small hole can be filled with epoxy.

Float Bowl Flooding

If a carburetter is flooding frequently or, worst case, overflowing fuel, it is likely due to either the float not rising (float holed and filled with gas or hung up on the float bowl gasket) or the float needle not seating well (needle worn out or dirt lodged beneath it).

Another possibility is that the fuel level is simply adjusted too high. That adjustment can theoretically be made by lowering the float needle seat. Tricky, but the Triumph Service Bulletin #2/73 (link just above) is there to guide you:

Float Bowl Leaking

Fuel leaks from the float bowl are sometimes the result of over-tightening the float bowl screws which causes the bowl to warp. If the leak occurs after changing the gasket, or after the bike has been sitting for a period of time with no fuel in the bowl, the leak may cure itself after the gasket has soaked and swelled up sufficiently to make a good seal. I have also stemmed this kind of leak with some Hylomar smeared on both sides of the gasket.

The official remedy is supposedly to flatten the float bowl by gently rubbing it on a sheet of very fine abrasive paper over a completely flat surface. Be aware, though, that removing an excessive amount of metal will affect the height of the float and float needle.

Assembling Cable, Spring, Air Slide, & Needle Jet/Clip

When refitting cable to air slide, don't try to compress the spring against the carb cover, away from the cable end. Instead, pinch the exposed (slack) wire cable with finger and thumb and push the cable (and spring) towards the bottom of the air slide until the cable pokes through the other side. So, compress the spring against the air slide, not the cover.

When installing the needle jet and its clip - that's when to scrunch the spring up against the carb cover, gently hanging the bottom end over and outside the carb body while you drop in the needle and clip.

Cleaning the Pilot Jet

The newer concentric carbs have a removable pilot jet which makes cleaning them pretty easy. On older Amals the pilot jets can't be removed so they must be cleaned in place.

Formally I used a guitar string to clear the idle jets, but some say this just pokes the dirt back upstream where gas will eventually wash it back down to the jets.

John Healy says to use a #78 drill through the pilot air screw hole to pull the dirt out of the jet and downstream:

"Use a #78 (.016") drill mounted in a piece of hobby brass tubing works the best. If you twirl it between your thumb and fore finger as you offer it, it pulls the swarf downstream of the jet to be washed away by the flow of fuel."

"Take the pilot air adjusters out and get a number #78 drill (0.016”) stuck to something like a spray can tube to extend it. Poke the drill (gently) in until you pick up the pilot hole, then twist. Afterwards, blow through with spray carb cleaner, and if possible compressed air."

Tuning the Mk1 Concentric Carburettor

Adjusting Low Speed Mixture & Idle Speed & Synchronizing Carburettors

The Workshop manual explains how to sync carburettors in Section B12: Setting Twin Carbs but forgets to mention final adjustment of cable adjusters.

Here is the basic routine for adjusting low speed mixture, idle, and synchronizing. For more details be sure to read Peg's post above!

It's a good idea to open the twist grip and then let it snap shut once or twice in between checking new synchronization settings for the cables.

Initial Synchronization of carburettors (no Low-speed adjustment)

Mid-Range Tuning

The next two sections talk about "8-stroking". If you're not familiar with the term, John Healy WWW icon

describes it well on Britbike.com.

Gavin Eisler offers this sage tuning tip on Britbike.com: "At half throttle, if acceleration could be better, no 8-stroking, clean running but slow to pick up maybe spits back as the throttle is opened, that's lean at the needle jet or needle position, try lifting the needle one notch..."

High Speed Tuning

A plug chop is one way to determine the correct main jet size, but there is an alternative. If engine power is flat above 3/4 throttle in top gear, begin increasing the main jet by two sizes at a time until the engine '8-strokes', then go down two sizes. So, to check if installed main jet is correct size, put in a jet two sizes up. If the engine '8-strokes' above 3/4 throttle, the smaller jet is the correct size.

Trouble-Shooting Carburation - Reading the Signs

When diagnosing carburetter problems, it can be extremely time-saving to first fully determine whether the problem is actually carburation or actually electrical. This is not always easy as they can seemingly mimic each other.

Once you're sure the problem is not electrical (but always keeping an open mind!) you can move ahead to carburation. But this is a good time to note that if you haven't yet marked your throttle positions the way StuartMac described, that essential step should probably be your first move in diagnosing or tuning the carb.

Whether you're diagnosing or tuning, observations and advice from veterans like these below will help turn you into a carburetter connoisseur!

Air Cleaners

Installing Air Cleaners

When using paper air filters, both air cleaners can be screwed on/off intact, but when using wire and gauze filters (thicker than the paper ones) the right-hand unit must assembled/disassembled in place due to interference from the foreword edge of the oil tank.

Air Filters

I prefer the wire gauze units because they are reusable. At first I washed them in kerosene, but now I just wash them with hot water and dish washing detergent. A water-based degreaser would probably work well also.

Control Cables

Lubricating Cables

Good cables last a long time if they are kept well-lubricated. Bonnie's throttle cables have been in service for seven years at the time of this writing and they are still completely serviceable.

My lubrication method is to disconnect a cable at the handlebars, tape its loose end into a funnel, fasten the funnel overhead, and pour in a couple thimbles of 10w or 20w oil to make its way down the cable overnight. Given this treatment once per riding season the cables only need an occasional few drops of oil to ferrules, nipples, and adjustors. And, of course, after exposure to rain.

Throttle Cables

Standard throttle cables for US bars are 43" - 45" depending on how they're measured.

A throttle cable routing that has worked well is for the TS cable to cross through frame beneath the gas tank to join the DS cable before they both pass between the front forks and up to the twist grip. I'm not sure what the hole in the TS headlight bracket is for, but it doesn't seem to work for the throttle cables.

When I got my Bonnie the throttle cables crossed over between the carbs and the twist grip. That is to say that the TS carb cable was connected to the inboard side of the twist grip and the DS cable went to the outboard side of the twist grip. That makes sense in terms of cable length and the routes taken, but I found balancing the carbs was more intuitive after I reversed the cables so their input and output ends were, so to speak, parallel.

Throttle Twist Grip

Use oil and not grease to lubricate the twist grip. Grease is too thick and the throttle will 'hang'.

Clutch Cable

Routing

I have successfully routed the clutch cable from the TS abutment on the outside gearbox cover through the frame beneath the gas tank to the DS and then through the front forks. However, I feel there is less friction when the cable arcs forward from the abutment and passes through the space between the gas tank and the forward gas tank bracket on the TS before passing through the front forks. A small cable-tie loosely securing the cable to the forward rocker oil feed pipe keeps everything tidy and in place.

Speedometer and Tachometer

Tachometer

Disassembly & Removal of Tachometer Drive Gearbox

After removing the gearbox from the crankcase always replace Sealing washer (70-7351, Ref.# 33 - same part used for gas taps) as well as o-rings as required.

Lubricating Tachometer Drive Gear

Unscrew tach drive plug and add grease after cleaning out as much old grease as possible. When plug is screwed in, excess grease will be expelled at cable connection to drive unit.

Tachometer Cable Lubrication

Speedometer

Speedometer Cable

The speedometer cable follows the swinging arm frame and then the main frame all the way to the speedometer head. It is held in place by three cable ties: one in front of the speedometer gearbox on the swinging arm frame, another on the main frame beneath the engine, and one on the frame near the front engine mount.

Tach & Speedometer Cable Lubrication

After inspecting a new speedo cable I purchased from Andy I wasn't sure if it was adequately pre-lubricated as I could just barely detect a light coat of grease. I emailed Andy and he replied that his cables are indeed pre-lubricated and ready to install. That's when I realized that I'd been over-greasing the cables!

So, apply a very light coat of grease after unscrewing the collet beneath the speedo/tach head and withdrawing the inner cable. When replacing the cable, be sure to verify that the ends are properly seated in the receptors of the speedo gearbox and speedo head.

Speedo Gearbox

If you're looking for a replacement speedometer gearbox and find yourself confused as to whether you need a 1.25:1 ratio or a 15:12 ratio, chill out: do the math and you'll realize that they are the same.

Speedo gearboxes are a slip fit on the rear axle. If you have difficulty removing one, it's possible that repeated tightening of the TS axle nut has swaged the gearbox casing, causing it to bind on the axle. In such a case it may help to "unscrew" the gearbox off the axle and then file the hole to its original size. According to Don this problem is more common on OIF models.

Speedometer Problems

A common problem with Smith's speedometers is a wavering or bouncing needle. Most frequent causes are poor cable routing, too much/too little lubrication, or use of too heavy a grease (see cable lubrication, above). An incorrect inner cable length (too short or too long) can also manifest itself this way.

If the speedo is inoperative, an electric drill (very low speed only!) to drive the cable or the speedometer head can be of help in isolating the problem.

Another common problem with Smith's speedometers is extreme stiffness in resetting the trip meter. These may help:

Some say removing the handle and spraying with lubricant or WD40 can fix this problem, but this sounds more than a little shakey to me. As previously mentioned, lubricants findng their way into the head are to be avoided.

Handlebars

Handlebar Styles

Follow link above for the extensive BritishCycle.com British motorcycle handlebar reference, with photos and dimensions.

Late '60s Triumph handlebars are 7/8" in diameter. Handlebar styles I've tried on my Bonnie are:

The Commando bars beautifully compliment Bonnie's lines, the wider USA bars inspire confidence on the gravel, and the UK bars are at home on the concourse.

Handlebar Shock-Absorber Mounting

For the handlebar shock-absorbing mounting to work properly, the parts must be installed in the correct order and the hemispherical washers must be oriented correctly, i.e. with their hemispherical sides facing each other.

It is also important that the hemispherical washers have indents around their inner hole. The indents match the shoulders on the shanks of the eye bolts and if they are not present the eye bolts can be stressed to the point of breaking. (John Healy). Illustration of correct assembly of a Triumph shock-mounted handlebars

Illustration of correct assembly of a Triumph shock-mounted handlebars

The correct order of the parts is listed below and shown in the figure to the right.

Removing Handlebar Mounting Bonded Bushes from Upper Steering Yoke

Handlebar Grips

After the hair spray debacle I tried the old school friction tape method next. Not plastic electricians' tape, but cloth friction tape. The first time I wrapped the handlebar with three layers. That worked well until a spell of very hot weather softened the adhesive and the layers of tape began sliding on each other.

Thinking that possibly less is more, I tried friction tape again, but using a single layer. Much better, but the grip still slides off. Very, very slowly, but it still slides off.

I'm going to try some rubbery hockey tape I have lying around and if that doesn't work I'm going to bite the bullet and get some Three Bond Griplock #1501C this winter. Very pricey, but presumably an effective solution.

As I write this it occurs to me that maybe I should try taking a rasp/belt sander to the handlebar.

Rear Suspension

Shock Absorbers

Disassembling Shocks

Dealing with the split ring clips at the top is much easier with two sets of hands.

Installing Shocks

When replacing the shock absorbers, instead of forcing the bushings into place from the rear of the frame bracket or from directly beneath the shock mounting holes, it may be easier to insert the bushings from beneath the spare hole in the forward part of the upper bracket, and then slide (bash with plastic mallet) to the rear and into place.

If the brackes are too tight for replacement shocks, as were Hagons I installed on Bonnie, cut a 5 or 6-inch block of hardwood the width of the brackets and use it to gently prise the brackets a bit wider.

The same bolt (14-0235) is used to fasten both tops and bottoms of the shockes to the frame. Bottom bolts have a plain washer (60-4246) beneath their heads and a lock washer (60-4259) beneath the nuts. According to #7, the bolts on top have no washer beneath their heads and a (different) plain washer (GS308) beneath the nuts.

Top and bottom bolts are shown in #7 with the heads outside and nuts inside. Installed that way, the end of the bolt on the DS may be interfered with by the brake drum cover. If so simply turn the bolt around. Nuts out also makes periodic tightness checks easier.

Front Fork

Front Fork Gaiters

Frank said it's "cheating", but gaiters can be replaced by simply removing the front wheel and fender. Pulling the tops of the gaiters past the dust excluder sleeve nuts is quite difficult, but pushing works well - dig the tips of both thumbs right into the top of the gaiter just below the "collar", and PUSH! Makes the job a breeze.

Replacing Front Fork Seals

Stanchion Tubes

The correct diameter of the stanchion tubes is critical for proper damping and also for a tight fit in the lower yoke.

As well, the profile and dimensions of the taper at the top of the stanchion tubes must engage the upper yoke sufficiently to prevent the tube from turning when the cap nut is tightened.

Before installing newly-purchased stanchions they should be carefully compared to the specs in the Workshop Manual's General Data section as well as the units being replaced.

Refitting Stanchion Tubes

Removing Front Fork As a Unit

Removing Front Fork Legs Separately

Dismantling Front Fork Legs

Reassemble Front Fork Legs

Rebuilding the front fork legs is not a terribly big job - it's not necessary to remove the upper and lower yokes from the frame, for example. But using the appropriate special tools, especially the stanchion tube puller, gives a huge advantage.

Refitting Complete Fork Assembly to Frame

To refit the complete front fork assembly (including the upper and lower yokes).

Aligning Front Fork

When replacing front wheel and axle, the front fork should be aligned as follows.

Steering Head

Removing & Replacing Steering Head Races

The front fork turns on 40 steel balls held by cones and cups, one pair on top and one at the bottom of the steering stem. Before beginning disassembly, spread a cloth to catch any steel balls that may fall out,

After the stanchions have been removed, the top cone/dust cover is removed by loosening the sleeve nut's pinch bolt and unscrewing the sleeve nut. Then, the lower yoke and steering stem can be dropped down and out of the upper yoke and headlugs (neck).

To renew the cups, drive the old ones out of the upper and lower lugs using a long drift. Strike evenly all around the edge against the protruding lips of the cups until they fall out.

A chisel or punch can just get a purchase on three sides of the bottom cone. Several good blows evenly around the three sides should break the cone free. Once a small space between the yoke and the cone has been opened, use two chiseles, one on each side, to wedge the cone free. The steering stem is shouldered where the cone fits, so the cone only needs to move about 5/8" before it is freed and pops off.

Replacing the cups is pretty straight forward. After placing the cups squarely against their steering lugs, use a hammer and hardwood block to drive them all the way in, taking care of course that they go in straight.

There is a special tool (61-6009) to install the lower cone, but the manual says a 9" piece of pipe with a 1-1/16" ID can be slipped over the steering stem and used to drive home the cup.

Refitting Upper & Lower Yokes

These steps are for installing the upper and lower yokes separately from the fork assembly - for refitting as part of fork assembly, see Refitting Fork Assembly to Frame just above)

Steering Damper

In 1969, only the TR6C came equipped with a steering damper. I found the dampers on my '66 Bonnevilles so useful that I retro-fitted one on Bonnie. Very good on bad roads and windy days, just be sure to loosen it when you get into town!

I think wind-induced deviation in down-road trajectory is at least as much due to its effect on the rider as it is the bike. Wind pushing against s rider's upper body moves their shoulders, thereby moving the handlebars with predictable results. A steering damper can eliminate the effect.

When retro-fitting a damper to Bonnie i neglected to fit 'locating pin' 97-2107, which, as i later learned TriumphDave's Britbike.com post, prevents the sleeve nut from falling off.

Steering lock

The steering lock cylinder is held in place by a counter-sunk set-screw. The set-screw hole is covered over by a plug which must be dug out before removing the set-screw and lock cylinder. Bonnie's is fubar, so i never let her out of my sight.

Axles, Wheels & Brakes

Axles

Front Axle

Triumphs use three different front axle widths, and between 1968 and 1969 the fork was modified in several other ways as well - not all of them compatible with each other, and not all well documented.

Wheel Building and Balancing

Front Wheel

The Nave Plate

Nave (knot knave) is a British term for a metal cover of a wheel hub, especially one which is chrome, stainless steel, or otherwise decorative. So, a hubcap.

To remove it, some say have at it with a couple of screwdrivers on the three tabbed spots. But removing the Triumph nave without permanant disfiguration may require at least a bit more finesse than that.

One proposed technique, that I've not tried, but sounds good, is to pry all three tabs simultaneously using hardwood sticks. The tips of the sticks must be whittled down a bit so they engage the tabs positively and either an assistent is required or elbows and knees must be pressed into service.

Front Wheel Bearings

Front Wheel Brakes

Removing Front Brake

Reassembly

Replacing Front Brake

Adjusting Front Brake

Front Wheel Fender Brackets/Stays

The front fender brackets (Ref.5 in Fig.26 Fenders ) fit on the lower fork legs pointing forward with the bottom angle projecting upwards.

Figure 26 (#7) doesn't show how the forward and center stays (Ref.2 and Ref.3) fit onto the fender brackets (Ref.5). They should both be fixed to the outside of the fender brackets Photo icon

as shown here.

If the fixing bolts are hard to get through the stays and bracket, slacken the bolts holding the stays to the fender and then give the bolts a rap with the plastic mallet.

[The mounting hole for the bottom stay (Ref.4) in Bonnie's used replacement lower fork leg is threaded, so the bolt must be threaded in and out.]

Rear Wheel

Rear Wheel and Chain Guard

Removing Rear Wheel (& Chain guard)

Either the wheel can be removed by lowering it through a specially-designed service table, or the back of the bike can be hoisted up to provide the required clearance between wheel and fender.

Replacing Chainguard

A nut and bolt fasten the front of the chainguard to a tab on the swinging arm frame. Replacement Parts Catalogue (RPC) #7 show the bolt inserted from inside the tab and outwards through the chaingaurd ((Ref.28,Fig.13,P.37 #7)). Some think this is an error.

For starters, oriented that way, the bolt can't be installed or removed while the fender is in place. Even more importantly, the bolt's head should be installed inside the chainguard, where otherwise any protrusion beyond the nut will snag the chain.

If you choose to install the bolt through the chainguard, though, you'll have to deal with the hastle of holding the thin Philidas self-locking nut in place while you start the bolt.

Replacing Rear Wheel

When re-installing the rear wheel, one must properly align the speedometer gearbox and then activate the rear brake somewhat forcefully (see "centering brakes below") while tightening the inner axle nuts. To do this the easy way, with the wheel mounted on the bike, you need a very thin 1-5/16" wrench for the TS inner nut. If you don't have a suitable wrench, save lots of trouble and get one.

Before I had the right wrench, I did all the above with the tire in a bench vise. But the problem was to get the speedo gearbox correctly aligned - a very trial-and-error affair. It's so easy on the bike - get the wrench!

Centering Rear Wheel Brake Shoes

The rear wheel brake shoes should be centered to the axle to prevent the brakes from 'pulsing'. To center the brake shoes, apply the brakes while tightening the inner axle nuts.

This is most easily done with the wheel on the bike because that facilitates aligning the speedo gearbox perfectly, and provides the use of the brake pedal for applying the brakes. But key to performing the work this way is the thin 1-5/16" wrench to tighten that TS inner axle nut.

Brake Torque Stay

Brake torque stay (ref 11 page 37) should go on before the plate for passenger foot peg and muffler bracket.

Both ends of torque stay are supposed to use the same nuts (14-0304)(3/8W) and spring washers (PCW73A), but on Bonnie one is thicker front) and one is thinner (rear).

The "C"-clamp on the torque stay adjusts the bottom of the chainguard with respect to the tire and the chain. It must be fit so that it rests ON TOP of the chainguard bracket to allow for adjustment. Bit of a PITA, but fitting the nut and bolt with the passenger peg and mounting plate removed is much easier.

Rear Wheel Bearings

Rear Wheel Brakes

Disassembly

Reassembly

Brake Pedal, Brake Rod, Brake Spring

Brake Pedal Wear

Over time, a Triumph rear brake pedal pivot becomes a loose fit. This would be an easy fix if Triumph had used a bushing there, but they didn't. Here's how one TriumphRat.net listee fixed the problem: WWW icon

TriumphRat.net WOL: "Sloppy Brake Pedal"

Assembling the Brake Rod

With everything assembled, it's nearly impossible to splay the cotter pin that fastens the rear brake rod to the brake pedal lever: therefore, do it at one of these stages of disassembly:

Replacing the Brake Spring

Should the "U-Hook" end of the rear brake return spring come off the brake arm, don't despair. The same "pulling" method used with the center stand spring will also tame this spring. Just make a few loops of cord, hook them over the end of the spring, and hoist it back on with one hand while using the other to hold the brake arm slighly forward.

Rear Wheel Fender Bracket

Replace

Rear fender bracket on frame 1/2" bolts (same bolt used for oil bottle bracket).

Rear Wheel Fender

Remove

Reassembly

Note that the two rear fender bracket mounting bolts (14-0113) Parts icon

(Ref 32 Figure 26) must be installed before putting on the fender.

Rear Chain

Removing Rear Chain

Replacing Rear Chain

Checking Rear Chain for Wear

As Burns points out in his article "Measuring Chain Wear", chains do not stretch, they become longer due to the pins wearing an oblong pattern in the bushes.

When wear progresses to the point the chain is no longer a perfect match with sprocket teeth, wear to both sprockets quickly accelerates.

How much wear is acceptable? Opinions differ. Extrapolating from 20 links to 100, the manual sets out 1.25" (1-1/4) as the maximum acceptable increase in length over 100 links.

However, Burns claims that "Most chain manufacturers limit chain wear to approximately .006" per link". That works out to .6" max wear per 100 links, or just under half what the manual considers maximum acceptable wear.

Which is right? I incline toward the figure suggested by Burns for the simple reason that a new chain costs less than a new chain and two new sprockets. And a lot less trouble to change!

Cleaning the Rear Chain

For asphalt riding I clean and lubricate the chain at each oil change, or every 1,000 miles for Bonnie. When I'm mostly riding the gravel I clean the chain every 500 miles.

Rear Chain Oil Feed

The rear chain oil feed is a hose from the oil tank to a fixed dispensing pipe that drizzles oil directly on the chain. The rate of flow is regulated by a tapered screw just under the oil tank filler cap. Most riders choose to shut off the oil feed supply and lubricate the chain manually. Adjusting the chain oil feed flow, or eliminating it, is accomplished by closing the adjusting screw all the way clockwise.

Manual Rear Chain Lubrication

In an old pan, immerse the clean chain in heavy (summer) chain saw bar oil for 20 minutes or more. Next, hang the chain overnight to drain excess oil. Next day, wipe the chain lightly with a clean rag before reinstalling.

Always lube a mounted chain when it's warm after a ride! Oiling a cold chain just makes a mess on the floor. Applied to a warm chain, oil will penetrate inside the rollers where it's needed instead of dripping off.

Using the tapered tip of a gear oil container, I apply heavy chain saw bar oil to the chain while I spin the rear wheel. It's surprising how much oil a warm chain will "absorb", but don't carried away! If oil drips off a warm chain the application was excessive and the excess will be flung off directly during the next ride. Performed regularly after every ride, very little oil is needed with each application.

Checking & Adjusting Rear Chain Slack

Britbike.com " Rear wheel adjustment" Another thread covering the finer points of rear chain adjustment.

The technical way of adjusting the rear chain is to disconnect the rear shock absorbers, prop up the swinging arm frame in the position where the chain is the tightest, and adjust for 3/4" inch up-and-down slack in the center of the chain's bottom run.

However, there is a shortcut method that will deliver the same result without having to disconnect the shocks.

With the bike on the center stand, rotate the rear wheel until you find the position that gives the most slack in the chain half-way between front and rear sprockets on the lower run. Now, with the chain in its slackest position, use a finger to push the lower run up and down. Adjust chain tension until the up and down chain slack is 1-3/4". That adjustment is the equivalent of setting chain slack to 3/4" at it's tightest position.

Note that when properly adjusted (1-3/4" slack on center stand, or 3/4" with chain at its tightest), the chain will look to have too much slack, but when a rider compresses the rear springs the swing arm raises, tightening the chain.

Tires

Tire Pressure

Although the General Data section of the Triumph Workshop Manual for 1969 Unit Construction 650 Twins states a tire pressure of 24 lbs for front and rear, it must be understood that the modern versions of even vintage tires are made with far superior materials and technology than the originals, and they are not only capable of higher inflation pressures, they require them.

The first few years I had Bonnie I used the WS manual's recommendation of 24/24. Eventually I took notice of the weird wear pattern on my front tires: they were cupping badly. The tire guy said raise the air pressure so I did, to 30/30. End of cupping problem.

Tire Sizes

Tire Styles and Treads

Frame - Stands - Tin - Pegs

Swinging Arm

Swinging Arm Incompatibility

Removing Bushes

Removing the bushes involves use of a substantial blunt force object and the proverbial "suitable drift" placed against the protruding edges of the inner ends of the bushes. A 2-lb sledge, a 1/2-inch drive extension, and a 13/16" deep socket whose end was ground to make a square edge worked admirably for me. Two or three solid blows got them moving and five or six more drove them all the way out.

Replacing Bushes

Before installing the new bushes, polish the bore of the swinging arm frame where the bushes go. I used 600 wet/dry followed by 1500. After the bores are good and smooth, give them a generous smear of grease before introducing the new bushes.

For an amateur like myself, the tricky part to putting in the new bushes is to get them to go in perfectly straight. The good news is, it's easy if you know a very simple trick.

There you have it. I couldn't believe how easy it was to keep the bushes "on-course". The concentric lines took all the guess-work out of starting the bushes on their way perfectly straight and keeping them straight all the way in. Don't be tempted to skimp on penciled circles - I made just three, but another time I would make quite a few more than that just for the peace of mind they bring.

So using the first line as a guide, tap the bush in using a plastic mallet. Once the bushes are off to a good start there are several choices: continue tapping them in with the mallet, or (better) draw them in using a piece of all-thread with a nut and washer at each end; or alternatively, press them in using a twin-screw woodworking bench vise.

Once both bushes are flush with the ends of the swinging arm frame they can be driven in the final 1/8" or so using a drift or a deep socket - a 1-1/8" Harbor Freight deep socket did the trick for me.

Reassembling & Replacing Swinging Arm Frame

(Note: Don't be tempted to put the shocks on before the swinging arm because they'll just be in the way).

In the swinging arm frame, assemble the two "sleeves" (Ref.5, Fig.13), spacer (Ref.6), flanged washers (Ref.7), and new o-rings (Ref.15), packing with grease as you go.

Next, using a wooden dowel to help line things up, insert the long S620 bolt (Ref.8). Loosely thread the nut on and use a grease gun to fill the cavity with grease. This will help keep everything in place while you install the swinging arm frame to the main frame.

Now remove the long bolt and offer the swinging arm frame to the brackets on the main frame. Use a plastic mallet to insert and position the swinging arm frame in the brackets until you can insert the bolt.

Remember that the DS main frame bracket is threaded for the S620 bolt, so insert the bolt from the TS.

Getting the long bolt inserted and lined up to thread into the DS of the main frame can be a fussy job. If fidgeting around and using a plastic mallet to align the swinging arm frame doesn't work, try using an impact screwdriver with a 9/16 BS or 7/8" socket. With a plastic mallet, tap the driver while slowly turning the bolt and it should start threading on.

At this point the swinging arm should be raised and lowered to determine that it lines up with the shock mounts.

Torque the long bolt's nut to 50 lb.ft.. If the swinging arm frame binds too much, back it off very slightly until you obtain the correct friction.

StuartMac tells us that the correct swinging arm friction can be judged as follows:

After tightening the bolt in the frame, install the tab washer (F5944, Ref.9) and S545 nut (Ref.10, Fig.13).

Sidestand

Remove

Easier to remove with stand folded against frame. Use 3/4" wrench to remove nut (faces out) and then give the bolt a rap to loosen up and start on its way out. Then open the stand and wiggle while pulling on the bolt. Slip the spring off after the bolt is removed.

Replace

Easiest way to get it on is to put the spring in place on the frame and the sidestand and then pull the sidestand into place.

Center Stand

Center Stand Compatibility

Replacing Center Stand Spring

Ever arm-wrestle a center stand spring? They're small but mighty! Many swear words have been uttered during center stand spring installations, but happily, there are techniques which can reduce, and possibly even eliminate the amount of brute strength required.

The easiest moment to install a center spring is before putting the stand on the frame and before putting the engine in the frame. Simply flip the frame upside-down and hold it down with your feet, using a towel to protect that new powdercoat of course. Then, hold the loose stand close enough to the frame to slip both ends of the spring into place, and then holding the stand by the legs, pull it into position and slip the bolts in. Easy-peasy! Note this technique relies on pulling instead of pushing.

Left/Right passenger footrest brackets

Remove

Remove left-hand bracket to make it easier to access the bolt holding the chainguard "C" clamp to the torque stay.

Brackets need to be slack to insert bolt for rear footpegs from behind - best to pre-assemble.

Rear Frame

The 21/34 bolt head is also 5/8", but its 21/34 nut is 11/16", spanner for the former and 1/2"socket for the latter.

Powder Coating

Bonnie's frame and tinware Photo icon

have been powder coated, as well as the following parts:

Battery Carrier

Replace Oil Tank and Battery Carrier Straps

Seat

To remove seat, first remove left side panel, then remove bolts for just one seat hinge and slip the other one off.

Install latch: install spring and washer with latch part way inserted, then push in all the way and insert the cotter pin - a pick works well to keep spring and washer in place.

The Triumph Nacelle

Of course the late 1960's Triumphs weren't fitted with nacelles, but if you're working on a pre-unit or certain unit models up to 1964 and need some pointers on nacelles, the above post by Deadstiffcatt should be very helpful.

The Electrical System

Trouble-Shooting Electrical Problems

Short Circuit

If your bike is blowing fuses, this trouble-shooting tip from John Healy will be a great help in tracking down the short: replace the fuse with a 12v light bulb and then begin disconnecting circuits one at a time. When the light goes out you're found the circuit which is shorted. Start looking for faults such as worn insulation or loose bare wires.

Lucas Wiring Color Codes

Wiring Diagrams

Bonnie Electrical System 2015 (no dip switch, no horn)

Bonnie Electrical System 2015 (with dip switch and horn)

Bonnie Electrical System Schematic 2006

Original Electrical System Schematic

Battery

Battery Specs

Replacement battery should be a sealed, maintenance-free unit with a minimum 9Ah rating.


Brand/Part#	Height	Width	Depth	Notes
Koyo YTX-12-BS	5-1/8"	5-7/8"	3-5/16"	5 stars, but hard to find
Motobat AGM MB9U	5.3" (13.6cm)	5.2" (13.3cm)	3" (7.6cm)	12v/11aH Popular for British bikes
PowerStar PM9A-BS AGM	5-1/2"	5-1/4"	3.0"	12v/9aH
PowerStar AGM PS-12-BS	5-1/8"	5-7/8"	3-3/8"
Yasua	5-1/8"	5-7/8"	3-3/8"	(Bonnie - June 2018)

Fuse

Resources

Workshop Manual (1969 650cc Twins) Section H12: Fuses

Use 35 amp British fuse (blow current rated), or 15 amp US fuse (continuous current rated).

When I fabricated my own wiring harness I fused both the positive and negative battery terminals.

Tip! Fusing both battery leads is effectively like having a spare fuse at all times because the positive battery lead can simply be shorted to ground without a fuse.

Once on a trip in the Green Mountains I turned on the ignition switch while coasting down a steep hill in fourth gear. Bang! A big pop and the negative lead fuse blew. No spare fuses with me - I'd left them on the workbench! I shorted together the positive fuse's carrier leads and put the good fuse in the negative lead.

Battery Carrier

Battery carrier inside dimensions: H x W x D.

For more info, jump to Battery Carrier section.

Alternator

Resources

Workshop Manual (1969 650cc Twins) Section H4: Charging System

Workshop Manual (1969 650cc Twins) Section H7: Alternator & Stator Details

John Healy "Lucas Electrical Stator or Rotor Install Guidance" (PDF)

Britbike.com Stator Installation J.R.C. Engineering "Lucas Alternator Tips and Hints" Descriptions & test procedures for Lucas alternators, rectifiers, and zener diodes -->

Stator Studs

Traps! If stator holes won't line up with the stator studs in the crankcase, or the rotor is off-center in the stator, do not be tempted to adjust the alignment by hammering on the studs. Doing so risks cracking the crankcase. Do any bending with the studs removed and held in a bench vise. (See stator link above).

Rotor Integrity

Resources

Triumph Service Bulletin "Loose rotor center or rotor retaining nut"

Lucas rotors are constructed in two pieces, the center and an outer part which holds the magnets. The center and the outer magnet construct are known to become loose from one another. This defect is not ordinarily repairable - replacement is customary.

A loose condition can be checked for by tightening the rotor in place with the stator removed, gripping the rotor with both hands, and turning the engine in both directions, checking for any slippage.

Rotor and Stator Clearance

Note: stator stud nuts torque spec: 30 lb.ft..

When reinstalling the rotor it's very important to ensure sufficient clearance (.008"-.012") between it and the stator - all the way around.

Here's a method often cited at the Britbike Forum:

Cut four to six pieces from a coke can (.004") that are about one inch longer than twice the width of the rotor
Fold them over double to make .008"
Off the bike, place the rotor inside the stator with the shims between them
Offer the rotor/stator/shim assembly to the stator studs
If necessary, use the assembly to push against the studs and adjust their position until the entire assembly slides easily all the way on
Install nuts and washers and tighten
Using pliers, grab the protruding shims and pull them out - they should slide out freely if clearance is good all the way around

Checking Alternator for Charging

With engine running and lights on, blip the throttle. If intensity of headlight does not increase with revs there is a problem somewhere in the charging system. This can also be verified by connecting a voltmeter (DC scale) across the battery terminals to see if voltage rises with revs.

The alternator can be checked independently of the rectifier/regulator circuits by connecting either a voltmeter (AC scale) or a 12 volt bulb across the alternator's disconnected leads and kicking the engine over.

Wiring Harness

Resources

Hermit.cc Original Wiring Harness - 2005

Hermit.cc New Repro Wiring Harness - 2006

Hermit.cc Custom Wiring Harness - 2015

Removing Main Wiring Harness

The selenium rectifier and grounding straps have already been disconnected.

Pull apart bullet connectors to tail light
Free tail light switch
Clamp from spring to brake rod has 5/16", or better, 1/8W nut and slotted bolt head
Disconnect wires (bullets) to contact breakers
Disconnect ignition switch and remove
Remove zener diode and bracket
If installed, remove bullet connectors to front brake light switch
Remove head light bolts
Pull harness forwards, through fork and out

Routing of Wiring Harnesses

(See original and repro photo sets above)

Main harness

Beneath gas tank. Tied about an inch to the rear from the "Y" (along with clutch cable) to upper tube through space in frame forward of the coils. Then tied again to upper tube just forward of the rear gas tank mount. Passes over the top of the rear loop into the battery area. Photo icon (Photo)

Horn/Dimmer harness (gray plastic)

Passes through the stanchions from the rear Photo icon (Photo)

2006: Eliminated horn and integrated dip switch wiring into the Lucas lighting switch in the headlight shell (see wiring diagram above)

Rear brake switch harness

2006: Tied just above bottom side cover mounting stud and then falls to follows the frame member before looping to the switch.

Bullet Connectors

Resources

Britbike.com Bullet connectors, crimp or solder? High caliber posts, no hollow points.

Britbike.com Electrical Work Advice and techniques for soldering.

Bullet connectors are compact, simple, and generally quite reliable. They sometimes get a bad rap for poor connections due to corrosion, but that issue is likely encountered primarily in very humid climates or coastal areas with salty air.

I recently learned that new bullets on the market are sized for metric wire and not the larger Imperial-sized wire found in original British motorcycle wiring harnesses. Accordingly, a modern bullet will not crimp tightly enough to original wiring, even if it's made for the appropriate number of wire strands. Inserting short wire 'shims' to pad out the larger size of the bullets might be a viable work-around.

Some bullets have two crimping points, one for the wires and one for the insulation. The wire crimp makes the electrical connection and the insulation crimp provides strain relief. Bullets available for British bikes today generally have a crimping point only for the wire.

There's some debate over whether it's best to crimp or solder bullets. Crimping provides a good mechanical attachment, and soldering insures good conduction, so to me it's logical to do both. There is, however, one caveat.

Traps! Unless done with care, soldering can actually reduce reliability.

When solder flows over individual strands of wire they become effectively solid and rigid. Without the flexibility of strands, solid wire is more prone to vibration stress and eventual breakage. Avoid this by using a very small amount of solder at the tip of the bullet and not allowing it to flow any further than the mechanical crimp. This will preserve the flexibility of the strands leaving the connection and help absorb vibration.

Tip! To keep the bullets from falling off the wire while you crimp/solder, strip the wire a wee bit long and splay the protruding ends slightly after inserting the wire into the bullet.

When finished soldering, prevent future corrosion by thoroughly removing traces of flux with a rag and warm water.

Soldering Recommendations

Never use acid core solder, only resin
Soldering paste is messy, nasty stuff, use solder with a resin core.
Match thickness of solder to the work at hand
For bullets and similar electrical contacts, my choice is 60/40 .031 diameter resin-core

If you have the nervous system of a squirrel you might succeed in using a dual-range soldering gun's low setting for soldering bullets, but something like a 35-watt pencil provides greater control over the process. Either way, use a clean, well-tinned soldering tip for best results.

Horns

Resources

Workshop Manual (1969 650cc Twins) Section H17: Twintone Horns & Relay

Workshop Manual (1969 650cc Twins) Section H8: Electric Horn

Figure 35 Ign coils, Horn, Rectifier, Zener diode

TriumphRat.net Twin horn relay wiring 1970 T120R

Headlight and Headlight Shell

Resources

Workshop Manual (1969 650cc Twins) Section H9: Headlamp

Workshop Manual (1969 650cc Twins) Section H10: Removing/Refitting Headlamp

Custom Headlight Shell Wiring Diagram Wiring Diagram, custom wiring

Headlight Reflector/Lense Fixing Clips

The headlight reflector unit (99-0686, or LUCAS 516798) is held in the headlight rim (99-0692, or LUCAS 553248) using fixing wires (99-683, or LUCAS 504665).

YouTube.com Classic British Spares: "Installing & Removing Lucas Headlight Wire Clips"

Triumph 650 Lucas headlight and rim photo showing mounting clip orientation

Triumph 650 Lucas headlight and rim photo showing mounting clip orientation

LED/Halogen Headlight Bulb Replacement

Resources

TriumphRat.net Head/Tail/Brake Light LED Replacements

Britbike.com thread Brett: "LED headlight bulb test: Now with Pictures!"

Tailight & Stoplight

Resources

Workshop Manual (1969 650cc Twins) Section H11: Tail & Stoplamp Unit

Workshop Manual (1969 650cc Twins) Section H16: Stop Lamp Switches

Warning Lights

Resources

Workshop Manual (1969 650cc Twins) Section H15: Warning Lamps

Lucas 35710 Light Switch

I've replaced this switch three times on Bonnie. After installing new repro switches I've attempted to recondition the old ones by taking them apart and re-assembling. Never had any success, maybe you're more lucky than me.

The figure below shows the internal connections of the Lucas 35710 (99-0563) light switch in all three positions. See also this chart-style pin-out for the 35710.
Diagram of Lucas 35710 Lighting Switch showing internal electrical connections

Ignition switch

Resources

Workshop Manual (1969 650cc Twins) Section H13: Ignition Switch

Workshop Manual (1969 650cc Twins) Section H14: Ignition Cut-Out Button

Traps! Repro editions of the Triumph ignition switch are notoriously prone to failure and the slightest weight of a key fob attached to the key is known to exacerbate the problem - leave your ignition key naked!

An intermittent ignition issue is frequently due to a defective ignition switch. If you're having an ignition problem, one of the first things to do is install a jumper lead from the battery to the coils, thus by-passing the ignition switch.

Connections:

Two Brown/White wires go on one of the switch's twin connectors
On the other are two white wires and one Brown/White wire

Zener Diode & Selenium Rectifier

Resources

Workshop Manual (1969 650cc Twins) Section H5: Zener Diode Charge Control & Testing

Workshop Manual (1969 650cc Twins) Section H6: Zener Diode Location

The zener diode is the voltage regulator. When alternator output is too high, it dissipates excess voltage as heat through its heat sink), thus protecting the battery from overcharging, as well as damage to other electrical components.

The selenium rectifier converts the AC alternator output to DC.

Both the selenium rectifier and the zener diode perform well, but if the pricey zener diode fails many will replace both it and the rectifier with a single solid-state device, such as a Podtronics or Tympanium.

Selenium rectifier connections:

Brown/White goes on the center terminal
White/Green and Yellow/Green leads go to the opposite outside terminals, matters not which on which side

Photo of Triumph 650 selenium rectifier showing wiring connections

Schematic diagram of Triumph 650 selenium rectifier wiring connections

Condensers

Condensers are only used when running on a points ignition system. They are fitted in parallel with the points and they have two functions to perform.

When the points first start opening, the condenser begins taking on a charge. This draws off the current which might otherwise arc across the small opening points gap. Then, when the points close and the coil's electromagnetic field begins collapsing, the built-up potential across the condenser is discharged through the coil, adding to the energy created in the high tension circuit.

A shorted condenser will create a no-spark condition. An open condenser will cause arcing across the points, pitting them and create misfiring.

To test a condenser with a multimeter, select the thousand-ohm range, place the meter's negative meter against the body of the condenser, and then connect the red meter lead to the positive terminal of the condenser.

If nothing registers, the condenser is open and it has failed
A good condenser will show a resistance reading that gradually becomes higher and higher
Reversing the leads will discharge the condenser, and the high resistance reading should rapidly collapse to 0 ohms

Ignition coils

Resources

Workshop Manual (1969 650cc Twins) Section H2: Coil Ignition System

Figure 35 Ign coils, Horn, Rectifier, Zener diode

Ignition Coil Heating Up

On a bike with a points ignition setup it is normal, but not desirable, for one or the other coil to heat up if the ignition switch is left on. This is due to current from the battery energizing the coil through the closed set of points.

If you need to work on the electrical system with the battery connected and the ignition switch in the on position, remove the points cover and slip a piece of paper or plastic between the contacts of the closed points.

EI (electronic ignition) units are programmed to automatically open the coil circuits after a set amount of time if the ignition switch is left on.

Installing Ignition Coils

Note that the head steadies must be installed before installing the ignition coils.

Clamps around coils are mounted beneath the brackets that mount to the frame
Over-tightening clamps can result in leakage or internal shorts of coils
Loctite may be a good idea
Mount coils as far to rear as possible without interfering with the head steadies - too far forward will interfere with gas tank - about 5/8" between blank end of coil and the bracket

Testing Ignition Coils

Note that just because correct resistance readings are obtained for a coil does not mean that the coil is good. It may be arcing internally or its readings may change when the coil becomes warm.

Resistance readings for 6v coils:

Between low tension terminals (-/+): 1.5-2.2 Ω
Between low tension terminal (- or +) and high tension terminal: ~4 KΩ
Between case and any terminal: ∞Ω

Resistance readings for 12v coils:

Between low tension terminals (-/+): 4.-4.5 Ω
Between low tension terminal (- or +) and high tension terminal: ~4 KΩ
Between case and any terminal: ∞Ω

Ignition Coil Wiring Connections

With Pazon

Left Coil (DS)

Black from module to -
Black lead from + to TS coil -

Right Coil (TS)

Red from module to +
- From + of DS coil

With Points and Original Harness

Photo Photo icon

Left coil

White x2 on top (-) ("1" on original coils)
Black/White on bottom (+) ("15" on original coils)

Right coil

Black/Yellow on top (+) ("15" on original coils)
White on bottom (-) ("1" on original coils)

Capacitor Ignition

Resources

Workshop Manual (1969 650cc Twins) Section H19: Capacitor Ignition

Capacitor ignition simply eliminates the battery by substituting a capacitor in its place. The "cap" is of the electrolytic type housed in a small metal can and spring-mounted to isolate it from those good, good, good vibrations. A capacitor does well powering an ignition system with points, although lighting will dim, flicker, and die at idle speed, and at low idle with lights on a bike can easily stall-out in the absence of highly-attentive throttle-blipping.

"Wild Thing" was equipped with a "blue can". Note to self: Photoshop those oil spots!

Caps don't work as well, or at all, with electronic ignition EI systems as they can't constantly provide the minimum required voltage to power such digital devices.

In addition to being stressed by vibration, electrolytic capacitors suffer from high temperatures and their electrolyte paste has a tendency to dry out over time in storage. Newly purchased capacitors should be tested at once using either one of the two simple methods described in the Workshop Manual (link just above).

Electronic Ignitions (EI)

EI versus Points

EI systems such as Pazon, TriSpark, Boyer, Rita, etc. offer some inportant advantages over traditional points systems:

Simplifies setting ignition timing
Highly reliable - set and forget
Identical timing setting for both cylinders means less engine vibration
More controlled advance curve reduces or eliminates pinging

The downside to EI:

When they finally die they are done for - not repairable
Require higher battery voltage for start-ups

To avoid being stranded by a dead EI system many riders resort to carrying a spare with them. A fairly common strategy is to "piggy-back" a spare "black box" with the unit in use to make a switch-over quick and easy should the first unit fail.

A well-adjusted points system will operate with little or even no battery charge. On the other hand, EI systems require a certain base voltage to run the electronics governing timing. Among all the EI systems Pazon is reputed to have the best low-voltage threshold for starting.

When faced with starting a bike with EI and low battery voltage, Peg offers us this logical start-up procedure.

Pazon Ignition

Resources

Pazon PDF Installation, timing, and trouble-shooting

Pazon Schematic Diagram

Wiring schematic for Pazon electronic ignition

Pazon - Trouble-Shooting

Nick, posting on BritBike.com:

"With the ignition on check you have 12 volts or so between the red and white wires on the Pazon and 12 volts or so between the coil supply and the white Pazon wire.
"Place a voltmeter between the Pazon black wire and the white wire, when you switch the ignition on the reading should be about 1 volt or so for a few/ maybe 10 seconds then it should go to 12 volts. (this is the unit switching the coils off under 'stall conditions' to prevent the coil burning out) It will cause a spark at the plugs if the coils are ok.
"If that doesn't work the black box unit is faulty or has been damaged.
"If it worked then connect one side of the sensor with the ignition on and momentarily touch the other sensor lead to its connector, this should also create a spark at the plugs. If it doesn't, check the resistance across the sensor connections, it should be between 120- 250 ohms from memory but sometimes vibration can break the track or the fine sensor winding connections on that plate.

"This will tell you if the box or the sensor is the problem."

Boyer Ignition Trouble-Shooting

Resources

VintageBikeMagazine.com "How to Trouble-shoot a Boyer Ignition" Includes good info relating to all EI systems

Podtronics/Tympanium Rectifier/Voltage Regulator Replacements

Resources

Podtronics: Instructions & Diagram

Britbike.com Podtronics vs Tympanium

Rectifier/Voltage Regulator Installing beneath battery carrier

Both the Podtronics and the Tympanium (as well as Sparx) are solid state devices that replace and perform the functions of the selenium rectifier (rectification of AC alternator output to DC) and the zener diode (voltage regulation).

The Bonnie Ref:
A Hyperlink Junkie's Illustrated Field Guide
to the 1969 Triumph Bonneville

Index

A B C D E F G H I K L M N O P R S T V W Y Z

abbreviations
adhesive/sealant products
adjust primary chain tension
adjust valve rocker clearance
air cleaners, install
air filters
air screw o-ring
air slide (carb)
align rear wheel
alpha-numeric part# conversion
Alternator
alternator, check
Amal parts, '69 650s
annealing head gasket
anti-seize compound
applying heat
assembly lube
axle retainers, rings, covers
axle parts, front illus.
axle parts, rear illus.
balance factor, crankshaft
Banjo bolts, orientation
Battery
battery carrier, dimensions
battery carrier, reassemble
battery specs & replacements
bearing retainer
bonded bushes, removing/installing
Boyer Ignition trouble-shoot
brake light, switch
brake light, switch harness routing
Brake, front
brake, front - adjust
brake, front - center shoes
brake, front - reassembly
brake, front - remove
brake, front - replace
brake pedal, D.S. engine mount, torque stay
brake pedal wear
Brake, rear
brake, rear - center shoes
brake, rear - disassembly
brake, rear - reassembly
brake shoe illus.
brake torque stay
breather pipe, installing
British motorcycle forums
British standard threads
bullet connectors
bushes, replace swinging arm frame
cables, lubricating
cable, speedometer
cable, speedometer - lubrication
cable, tach
cable, tach - lubrication
cables, throttle
camshaft, timing
camshaft bushes, renewing
camplate, all positions illus.
camplate, positioning for indexing
Carburettor
carburetter cables,air slide,spring
carburetter choke
carburetter, clean idle jet
carburetter, concentric cross-section
carburetter, flooding
carburetter, jet/needle/cut away
carburetter, float bowl leaks
carburetter O-rings
carburettors, specs & settings
carburettors, synchronizing
carburettors, remove as unit
carburettors, trouble-shoot
Carburettors, tune
  Amal tuning links
  high speed
  low speed & sync
  mid-range
cat in a toilet
Center stand
center stand spring
center stand hardware compatibility
chainguard, replace
chain, see Primary Chain
chain, see Rear Chain
Clutch
clutch, adjustment
clutch hub & center, assemble
clutch hub, center,duplex install
clutch cable
clutch hub extractor
clutch hub/thrust washer compatibility
clutch drag, causes of
clutch lever pull too heavy
clutch operating mechanism "pops"
clutch pack thickness, Triumph & Aerco
clutch plates, replacing
clutch pressure plate adjustment
clutch problems
clutch springs, specs
clutch rod adjustment
coils, see ignition coils
color code, wiring
Colorado Norton Works oil filter adaptor
compatibilities, index
compression, sudden loss of
condensers
Connecting rods
connecting rods, assembly of
connecting rods, older/newer types
connecting rods, tightening
connecting rods, shell bearings
connecting rods, updated torque spec
contact breaker points gap
Crankcase
crankcase breather, testing
crankcase breather pipe
crankcase junction studs
crankcase oil, change
Crankshaft assy
crankshaft oil seal orientation
crankshaft, balancing
crush, cyl head and PRTs
cups and cones, renewing
cylinders, displacement and overbore
cylinders, rebore
cylinders, hone
cylinder base bolts, remove
cylinder block & tappet blocks
cylinder block, repros
cylinder block, painting
Cylinder Head
cylinder head bolts leaking
cylinder head bolts re-torque
cylinder head bolts torquing
cylinder head bolts torque error
cylinder head gasket
cylinder head, recessed valve seats
cylinder head, removing stuck
detonation, pre-ignition
distance pieces, rear axle
duplex sprocket, install
EI (electronic ignitions
EI versus points
Electrical
electrical, Pazon ignition
electrical, Podtronics
electrical, schematic diagrams
electric wiring color codes
Engine
engine breather pipe, install
engine compression
engine, installing
engine mounting plate fasteners
engine, removing
engine sprocket, align w duplex sprocket
engine sprocket, install
engine temperature, chart
exhaust system
exhaust pipes, removing
exhaust leaks, sealing
fastener specifications
float and float needle
flywheel, factory changes to
footpegs and brackets, passenger
forums, British motorcycles
Frame
Front Fork
front fork, alignment
front fork, dismantle

front fork gaiters
front fork legs, rebuilding
front fork oil
front fork, remove as unit
front fork, remove legs separately
front fork seals, replace
Front wheel
front wheel bearings
front wheel brake
front wheel brake shoes illus.
front wheel fender brackets/stays
fuel lines
fuel lines, plastic and safety
fuel lines, remove carbs with
fuel lines, remove from gas taps
Fuse
gaiters, front fork
gasket, head gasket
gasket, primary cover
gaskets, general
gaskets, rocker box
Gas tank
gas tank, paint schemes
gas tank sealers/liners (link)
gas taps, rebuilding/lubricating
gas taps, remove/replace
gas taps, sealing leaks
gear cluster illustration
gear cluster installation
gear oil change
gear oil & yellow metal
gear ratios, 4/5-speeds
gears, clunking
gears, illus.
gears, 4/5-speed tooth counts
Gearbox
gearbox, animation
gearbox assy, best way
gearbox assy, 4 ways
Gearbox bearings
  identification
  DS mainshaft bearing,remove
  DS mainshaft bearing,replace
  TS mainshaft bearing,remove
  TS mainshaft bearing,replace
  DS layshaft bearing,remove
  DS layshaft bearing,replace
  TS layshaft bearing,remove
  TS Layshaft bearing,replace
gearbox illus.
gearbox problems - resources
gearbox, index camplate & quadrant
gearbox inner cover
gearbox inner cover, remove
gearbox inner cover, replace
gearbox jumps out of gear
gearbox outer cover
gearbox outer cover, remove
gearbox outer cover, replace
gearbox, sealing inner/outer covers
gearbox sprocket
Gear change mechanism
gearshift camplate positions
General Data T120/TR6
General Shop Info
gudgeon pins, remove
gudgeon pins, replace
Handlebars
Handlebar grips
handlebars, shock absorber mtg.
handlebars, remove bonded bushes
head bolts, see cylinder head bolts
head gasket, anneal & install
headlight bulbs, breaking
headlight bulb LED/Halogen
headlight reflector fixing wires
headlight shell wiring diagram
heating cases & other parts
heat insulation, carbs
hollow dowel tips
hollow dowels, crankcase
hollow dowels, PN corrections
honing cylinders
horns
horn/dimmer switch harness routing
idle screw o-ring
ignition coils, installing
ignition coils, heating up
ignition coils, testing
ignition coil wiring connections
ignition switch connections
Ignition Timing
ignition timing, complete
ignition timing, 6CA illustrated
ignition timing, dynamic (6CA)
ignition timing, static (6CA)
ignition timing, 4CA WWW icon

links
index, compatibilities
index, tips
index, traps
indexing gearbox camplate & quadrant
kicking back
kickstart lever tapered pin
kickstart mechanism
kickstart problem, diagnosing
kickstarter, freeing when jammed
layshaft bearings, removing
layshaft bearings, replacing
layshaft end play, measuring
layshaft thrust washer locating pegs
Loctite, where to use
Lowbrow 650 Rebuild Video Index
Lucas wiring color codes
Lubrication Schedule
maintenance
main bearings, replacing
main jet
mainshaft bearings, removing
mainshaft bearings, replacing
manuals
manuals, download
muffler baffles, rattles
mufflers
nacelle
nave plate, remove
needle
needle jet
needle jet pin gages
O-Ring Sizing Chart
o-rings, carb to intake manifold
o-ring dimens., PRT seals
o-rings, front fork dust excluder sleeve
o-rings, idle, air screw
o-ring, carb mounting
o-rings, pushrod tubes
o-rings, swinging arm
o-rings, rocker spindles
o-rings, tach gear housing
oil, zinc content
oil breather line
oil change, crankcase
oil drain down
oil filter
oil leaks, drain bolts
oil lines
oil pump
oil pressure switch
oil pressure relief valve
oil seal, crankshaft
Oil tank
Oil tank, '66 defective
oil tank, reinstalling
online resources
paint schemes
parts lists, downloads
parts lists, Hermit's
part numbers, conversion of
parts suppliers
patent plate, replace
Pazon Sure-Fire PDF
Pazon, schem. diag
Pazon, setting timing with
Pazon, trouble-shoot
petcocks, see gas taps
pilot air screw
pilot jet
pin gage for needle jet
pinion gear removal
Pistons
pistons, remove gudgeon pins
pistons, remove stuck pistons
pistons, replace gudgeon pins
piston rings, gap
piston board
piston skirt clearance

piston rings, install
piston rings, orient.
Podtronics, regulator/rectifier
points, ignition
points, adjusting with 6CA breaker
points, adjusting with 4CA breaker
points, contact breaker gap
points versus EI
powder coating
pre-ignition/detonation
pressure plate, adjusting
primary chaincase
primary chaincase gasket
primary chaincase inner cover
primary chaincase oil, change
primary chain. adj.
primary chain, check wear
primary chain, install
primary chain wear, photos
pushrods & rocker boxes, replacing
pushrod tubes (PRT)
pushrod tube o-rings
pushrod tube seals
pushrod tube o-ring/seal dimen.
pushrod tube seal "crush"
pushrod tube installation
quadrant, gearbox indexing
Rear frame
Rear Chain, adjust slack
rear chain, check wear
rear chain, clean
rear chain oil feed
rear chain, removal
rear chain, replacement
rear chain, lubrication
rear wheel
rear wheel alignment
rear wheel bearings
rear wheel brakes
rear wheel brake shoes, illus.
rear brake shoes, center
rear wheel fender
rear wheel fender brackets
rear wheel, remove
rear wheel, replace
relief valve, oil pressure
re-torque head bolts
rings
rings, gap
rings, install
rocker spindles, assemble
rocker spindles, types of
rocker spindle o-rings
Rocker Boxes
rocker box gaskets
rocker box gaskets, lightweight pr mod
rocker boxes, remove
rocker boxes, replace
rocker clearance, adjust
rods, see connecting rods
roller bearing, steering neck
rotor, loose center
rotor installation guide
rotor nut, torque
rotor to stator clearance
Sealants, applications and characteristics
Seat
selenium rectifier connections
serial numbers, 1950-1969
serial numbers, 1969-1983
service bulletins
shell bearings
shift linkage (illus.)
shock absorbers, rear
shocks, disassemble/install
side panel
sidestand
slide (carb)
skirt clearance, pistons
sludge trap
soldering
spark plugs
Speedometer
Special tools
Speedometer and Tachometer
speedometer cable
speedometer gearbox
speedometer gearbox lube
speedometer gearbox ratios
speedometer problems
sprocket, gearbox - replace
stanchion tube, as drift for lower cone
stanchion tubes, compatibility
stanchion tubes, replace
stator installation guide
stator studs
stator to rotor clearance
steering damper
steering head
steering lock
stoplight
studs, crankcase junction identified
studs, cylinder base, hollow dowels
studs, cylinder base, through-drillings
studs without "pips" (Trap)
Swinging arm frame
Swinging arm, correct friction
switch, Lucas 35710, connections
switch, ignition
switch, brake light (rear)
Tachometer
tach cable, lubrication
tach drive gearbox, remove
tach drive gear, lubrication
tailight
tangs, shell bearings
Tappet guide blocks
tappets
Thackary spring washers
thread locker
threads, types of
threads, list of left-handed
throttle cables, routing
thrust washer (clutch)
thrust washer (clutch) and GL5
thrust washers (gearbox)
thrust washers (gearbox)
thrust washers (rocker arms, Thackary)
tickler
Timing Chest
timing chest, disassembly
timing cover, removal
timing cover, remove WWW icon

links
timing, see ignition timing
tips, index
tires, Dunlop tech ref. (PDF)
Tires
pressure
size
style,tread
tools, special
torque settings, head bolts
torque stays, engine
Transmission
transmission, assemble
transmission, dismantle
trap door (pri chaincase inner cover)
traps, index
trip meter handle won't turn
trouble-shooting, carburation
trouble-shooting, electrical
upgrades, sensible WWW icon

Valves
valve clearance, adjust
valves, replace in head
valves, recessed seats in head
voltage rectifier/regulator, Podtronics
Warning Lights
wet sumping
Wheels
wheels, building/balancing
wiring, Lucas color codes
wiring diagrams, elec. system
wiring diagram, headlight shell
wiring harness
wiring harness, horn/dimmer switch
wiring harness, rear brake switch
wiring harness, remove (stock)
wiring harness, remove
wiring harness, routing
Workshop manuals, factory
wrench jaw gap sizes
yellow metals & gear oil
zener diode
zinc, in motor oil

A B C D E F G H I K L M N O P R S T V W Y Z

The Bonnie Ref

Icon Legend

Triumph Documentation

Workshop Manuals

1969 650 General Data

Triumph Service Bulletins

Sources: Replacement Parts Catalogue & Service Manual Downloads

Parts

Sources: Replacement Parts Catalogue Downloads

Alpha-Numeric Part Number Conversion

The British Motorcycle Fastener Database

Triumph Error Database (Corrections to RPC Errors)

Hermit's 1969 650 Parts Lists: Hyperlinked & Illustrated

Torque Settings

Parts Sources

Suppliers

North America

United Kingdom

Special Tools

Special Tool Lists & Illustrations

Other Online Resources

Triumph Models

Online Forums

Classic British MC Links - All links No ads

General Shop Info

Abbreviations

Left-Hand Threads

British Motorcycle Fasteners: Threads

SAE threads

UNF

UNC

The British standard threads

BA

CEI/Cycle/BSC

BSF

BSW

BSPP, BSPT

Wrench Jaw Gap Sizes

Loctite Thread Lockers

Where to Use Loctite

The Loctite Gospel: According to John

The Loctite Gospel: According to Thomas

Loctite Thread Locker Characteristics

Loctite Red

Loctite Blue

Loctite Purple

Sealants

Sealants: Where? and What Kind?

Sealant Product Characteristics

Loctite 518 Sealant

Loctite 574 Sealant

Hylomar Blue Sealant

Three Bond 1130 Sealant

RTV Sealant

Wellseal Sealant

Gaskets

Bearing Retainer

Assembly Lube

Applying Heat

Lubrication

Routine Maintenance & Lubrication

Engine Lubrication

Diagram of Triumph Unit 650 Engine Lubrication System

Selecting an Engine Oil

Changing Engine Oil

Using an External Oil Filter

Filters for use With standard Norton filter head

Colorado Norton Works Filter Adaptor

The Oil lines

Oil Line Connections for Stock Condition - No External Oil Filter

Feed Oil Line

Return Oil Line

Scavenge Feed to Rockers

Oil Line Connections When Using a Norton Filter Head

Removing Oil Lines at Oil Junction Block

Crankcase Breather

Oil Breather Vent Tube

Oil Pump

Oil Pressure Relief Valve

Oil Pressure Switch