Was having the usual insomniac mind wanders last night and one of the things that crossed my mind was that perhaps our gallant home engineers who convert enfields to diesel are approaching thing the wrong way..
They look at bikes, look at diesels, mentally combine the two and the obvious answer is to use a pre-unit gearbox (heavy) which is easiest if we use a pre-unit frame like an enfield (also heavy) fitted with otherwise standard (heavy) parts... which knackers the already limited performance.
Perhaps a better approach might be to pick a nice light chassis/bike (lighter the better) and take the drive straight out the engine to a bicycle style derraileur gearchange... light, efficient and compact...
What d'ya think? Would a mountain bike transmission handle the awsome power of a Yanmar (copy) diesel?? The modern stuff is pretty reliable with 15 stone thugs stamping down on it!
I reckon if it worked it would take the dieso bikes from slug to useable *and* improve the already remarkable economy.
Of course I could be talking complete horlicks

lol