Re: TRIUMPH T 100 R / T 100 RR I always used a 4 speed CR gearbox, but after I sold the bike to a friend he fitted the late 5 speed Triumph box. I thought it would present difficulties with that short stroke. But I rode it a few years ago and it was quite OK. I believe Phil Pick sells two pairs of gears for that box which move second and third up a bit. It's just a pity that the unit motor doesn't present similar opportunities. A decent CR gear box is essential for a short stroker. Most other things about the late unit motor are good. To explain about the gearbox - when you are building any road racer, the first thing t o look for is a decent close ratio gearbox. If you cannot find one, your efforts to make a fast bike will be in vain. You can end up with a bike that almost stalls in certtain places around tight circuits, and you can never be smooth on it on downshifts. I rode my Seeley commando with a standard box - it was revolting. Some guys who have never used a close box thing the standard box is OK - they need the experience of using the good thing.