I was inspired by Les Fishers performance on a factory model, and bought a road model of a friend. The trick was the rider,not the bike.
I lengthend the swinging arm to allow 19" rims to be spoked into the original 16" wheels, got the specs for the ports of the factory model and modfied them to the same. It went reasonable but I dis-owned it after it blew a crankcase seal at the top of the infamous "sorbent hill" and shot me off into orbit.
It also had some other built in demons that needed mods.
cheers pancho