TechNotes: Triumph 650 Tech Articles

"Classic British Motorcycle Tires Illustrated"
Tires have come a long way since Dunlop K70s ruled the roads. New profiles and new materials improve performance but sacrifice the classic look of tires from back in the day. Let this tire guide, with it's tread photos and rider reviews, help steer you to the right decision for your bike.

"Triumph 650 Ignition Timing"
Having trouble setting the ignition timing on your Triumph 650 points ignition? Then you've come to the right place! Hermit's illustrated guide to setting points ignition timing identifies and explains exactly what the heck each and every one of all those little screws in there do! Includes detailed, step-by-step instructions for both static and dynamic timing.

"Triumph Unit 650 4-Speed Gearbox Assembly Made Easy"
Of all the different ways of assembling a Triumph 650 gearbox, the standout method has to be that demonstrated by the masterful Hughie Hancox on his authoritative "Unit 650 Engine Rebuild" DVD.

"Triumph Gearbox Assembly: Comparing Three Different Methods"
If you're still not convinced that the Hughie Hancox method is the best, here is a side-by-side comparison of the methods shown by the Triumph workshop manual, Haynes, and the master himself, Hughie Hancox.

"Indexing the Triumph 650 4-Speed Plunger Gearbox"
The Triumph 650 gearshift mechanism illustrated and explained followed by step-by-step instructions for three different methods to index the gearshift quadrant to the camplate.

Triumph 650 Gearbox Photo Animation: Front View
Hermit's Triumph animation shows all the movements of the gear cluster and camplate through all gears and neutral.

Accompanying still photos use color-coded diagrams for you to see the transfer of power from the mainshaft through all four gears (and neutral) to the gearbox sprocket.

Triumph 650 Gearbox Photo Animation: Rear View.
The same great gearbox photos and photo animation but viewed from the rear.

Highly educational.

Hermit Gearbox Articles Index
Links to all the gearbox materials on hermit.cc.

The Spring Report - Mike James
Between '68 and '70, Triumph made many tweaks to 650 Triumph gearbox plunger springs, plungers, plunger holders, and gearshift camplates. What did it all mean? Mike James evaluates and analyzes the changes in this detailed and superbly illustrated guide. Learn the difference between spring rate and spring force and why it matters. A must-read for those interested in a deeper understanding of these intricately related parts and the method to Meriden's "madness". (PDF, 8.5mb)

Triumph 650 Gearbox Components Reference Photos
Reference photos of Triumph Bonneville 650 gearbox components - assembled and apart. Photo comparisons between different versions of the same parts.

The Gearbox Section of `The Bonnie Ref'
Loaded with illustrations, this is a complete guide to maintaining, trouble-shooting, disassembling, assembling, and indexing the Triumph 4-speed gearbox. Includes factory bulletins and links to many other gearbox resources.

Assemble Clutch Hub, Rollers, and Clutch Center
Photos showing assembly of the clutch hub, rollers, clutch center, and duplex sprocket, with link to step-by-step instructions.

Proprietary Clutch Locking Tool
A couple of used clutch plates and a short piece of iron pipe are all you need to make a handy tool which is essential for clutch and gearbox work.

The "Triumph 650 Unit Construction Engine Overhaul Manual", written by Thomas G. Gunn, Jr. for Triumph Corporation Baltimore in 1967, is a field-tested, step-by-step blueprint for completely overhauling the iconic unit construction Triumph 650 engine. It lists engine changes and updated factory specs up until 1967.

In addition to correcting errors in the original and further updating technical info, Hermit's hypertext version offers seamless, one-click access to footnotes, table of contents, and direct links to corresponding sections in the 1969 Triumph Workshop Manual.
Have a look:
Triumph 650 Complete Overhaul Manual: Hypertext Version

Pushrod Alignment
Here's an idea for getting those pushrods properly aligned with the rockers during reassembly, even if you're using larger diameter custom lightweight pushrods.

An Inexpensive Homemade Motorcycle Table
Working on your bike with it up on a table simply can't be beat. Table lifts are expensive, but this homemade version won't break you.

Installing a New Center Stand Spring
The easiest way to install the pesky center stand "super-spring". Some things are easier to pull than push!

Ecclectic Collection
I've just gathered a lot of images from around the hermit.cc site and linked to them here. Kinda fun to browse. A few of these do not appear elsewhere on the site.

The Usual Suspects
To dispell my confusion about the assembly order and orientation of front and rear axle rings, retainers, and dust covers on my 69 T120R, I organized these illustrated, cross-referenced parts line-ups. I also included photos identifying the rear axle nuts and distance pieces. Illustrations include descriptions, RPC pages and figures, part numbers, and specs.

Triumph T120 Fork Dimension Changes for 1968/1969 - Mike James
Mike James guides us through the mine field of subtle changes that Triumph made to fork components during the years 1968 and 1969. Part numbers, specs, and illustrations to help you sort out your late-sixties Triumph front end. (PDF, 5.3mb)

NOTE: For what it's worth, Triumphrat Vintage & Veteran moderator StuartMac seems to take exception to a) Mike's proposed reason for increased width of the 1969 model year forks, and b) Mike's suggestion that some later 1968 sliders required unified thread hardware. Read his posts here and here.

650 Triumph Front Fork Rebuild
Here are illustrated step-by-step instructions for reassembling the front fork for a 1969 Triumph T120R. Complete info, including rundown of special tools.

Wheel Rebuilding - by Phone
You can't tune a fish, but you can tune a motorcycle wheel..

If you don't know a hop from a wave, let guest tech writer Geoff Collins roll out the basics for you in this article about his first-time wheel rebuilding experience.

On the same subject, Peg spoke well in her most excellent tip-laden wheel building treatise: a step-by-step method full of sage advice. With photos. A must read. On TriumphRat.net.

Rear Wheel Alignment Using Mason Line
Proper rear wheel alignment is crucial to preventing excess tire, sprocket, and chain wear. If you're unfamiliar with working to a line, here are some tips on how to set a line on your bike to check alignment.

Pin-Out for Lucas 35710 Lighting Switch
Here is a chart showing the electrical connections in all three positions of the Lucas 35710 lighting switch (Triumph Part # 99-0563).

Blimey! Why do my headlamp bulbs keep breaking?
Because you keep dropping them on the shed's cement floor? Because your pothole radar is defective? Or because you forgot to grease them?
Seriously! Also, some helpful(?) 'insights' on headlamp bulb test methodology from our own in-house motorcycle mechanic extraordinaire, Bardfark Dungwall.

The Bonnie Ref: A Hyperlink Junkie's Illustrated Field Guide to the Triumph Bonneville
The Bonnie Ref is a compendium of information about caring and repairing the 650 Triumph Bonneville. Includes ramblings of Bonnie's non-mechanically inclined owner. It's a warehouse of highly organized easily-accessed info, including factory service bulletins, photos, full parts, and links to informative on-line discussions.

Hans Muller's 1942 BSA WDM20 Restoration
For all our BSA riding mates, here's a great personal story from Hans Muller about his marvelous 1942 BSA WDM20 restoration.

Hans' article also includes illustrated descriptions of his restoration as well as WDM20 Service Notes, Wiring Diagram, and complete parts list.

The Polar Bear Rides Again!