TOMCC is privileged to have secured the services of Nigel Sprocket, ex Triumph UK to give us the benefit his advice, and to add interest with anecdotes from his years at the Triumph factories.
Nigel joined Triumph in 1903 as an apprentice on the shop floor. He moved with the company to Meriden where he was soon promoted to Head draughtsman on the parallel twins project as a result of his ground breaking work on preventing leather drive belt slippage. When designer of the first Triumph parallel twin, Val Page, pointed out that Triumph hadn’t used belt drive for thirty years and he had already developed a parallel twin engine, Val was immediately transferred to BSA. (as an aside Val’s engine eventually became the BSA A7/A10 range).
Nigel moved on to develop Harris Bonnevilles where his innovative work on saving weight by developing porous castings astounded Harris Bonneville owners worldwide.
When John Bore started Hinkley in a stunning coup he poached Nigel from the dole queue to work in the experimental department where to this day he is developing a standard whitworth thread pattern not only for Hinkley bikes but eventually for all motorcycles. Imagine only one set of spanners required and they’ll be British!
The first step is to get the throttle slides both opening at the same time. This is easy when the carbs are off the bike and I always check this when I have them off. It’s a bit harder on the bike especially with splayed heads. The way I do it is wind the throttle …
The trap in the crankshaft is hard to remove but is a must do whenever the bottom end is apart. I learnt this lesson as a youngster when I rebuilt my 500 Trophy in a corrugated iron lean to at the back of the commune (yeah alright, bloody hippies, but this was in the very …
If your 650 engine no is between DU44394 and DU887147 then you can reduce running temperature and therefore extend engine life at no cost, next time you have the crankcases apart. From DU44394 an oil pump with better scavenge capability was introduced and after DU887147 the crankcase oil level was increased by shortening the length …
Follow the manual to remove the valve covers etc and measure valve clearances. This is where my brain starts to hurt as my feeler guauges are imperial, and I think in Thou, and I have trouble keeping track of what shim I need and where it goes. Try this spreadsheet Valve Shim enter clearance in thou, existing …