After 88,000 miles and many top-end refreshes and overhauls (at least one of them overly agressive) Bonnie's valve seats were recessed to where engine efficiency was suffering considerably. Something needed doing!
First inclination was have Bonnie's head reconditioned, valve seats and all. Trouble is, replacing valve seats on a Triumph 650 head is a very tricky job and finding someone to do it is not easy.
In fact it was proving so difficult that I began looking around at used cylinder heads. EBay presented many Triumph heads for sale, from a couple hundred bucks and up. I was quickly convinced, though, that buying a pig-in-the poke Triumph cylinder head was not a good way to go.
So how about a reconditioned head through a reputable parts supplier? Scarce is the by-word. The few are pretty expensive, but in spite of being shiny still have recessed seats themselves. So if I already have the head, surely I can do better than this?
So I come around again to the idea of new valve seats for Bonnie's head. I find a well-known, higly respected West-coast shop that advertises the service. Am I afraid of a little expense for the Bonnie? Noooo, not me! But sadly, the service is not actually available. But try so-and-so. So-and-so was a no go and I despaired.
That's when I got in touch with the most dependable supplier I know. Mitch was less than sure about it, but after contacting a local machinist on my behalf, said the guy could do it.
The results met and surpassed my greatest expectations. The Bonnie engine is effectively at 0 miles, and its performance is restored to like-new!
I'll try to get back here and link to the photos of Bonnie's new head when i post them.
Intake Drive Side.
Intake, Timing Side.
Intake, DS/TS.
Drive Side exhaust valve seat.
Drive Side intake valve seat.
Timing Side exhaust valve seat.
