Triumph racer project

In the July 2022 issue, in the readers’ letters, there was a bit about Tony Page buying a Bandit frame. I have been trying to get a Percy Tait-type Triumph built to go racing and this frame is very much like the special frame Ken Sprayson built for Percy.

I did speak with Ken and he told me the frame Percy used was a modified version of the old Enfield GP racer; actually, the frame was wrong with the engine too far back, so he made another one for Percy. Interesting, Percy and his crew always referred to this bike as ‘the Enfield.’ The ‘Enfield frame’ was virtually destroyed by someone using it for motocross. But from what I have found out, the Bandit frame was very similar, not a big stretch of the imagination really as Percy was doing very well with his bike, so when they thought of the 350cc twin, you could see the reason to use the design.

I have been working on the Triumph 500cc unit twin with a view of taking it to the spec the factory would have used. Interesting, Norman Hyde did the drawings for a short stroke engine using a bore of 73mm (up from 69) so this is what I am working on, I will have some new cylinders cast in alloy and I have already got some new pistons made. The one thing I did find out though was the 500 vibrated very badly at high revs. To this end I am making a new crankshaft in En40b with the journals spaced 76 degrees apart, as Phil Irving suggested to the Triumph factory, way back in the early days.

It is a peculiar thing but for a quirk of fate the Triumph factory might have investigated this and found that it did greatly reduce vibration. How might the Bonneville have progressed if it could have grown bigger without increasing vibration? (what if). Funny thing is Rex McCandles also offered the ‘Featherbed’ frame to Triumph first, so the Triton might have been the real bike all along (what if ).