A retired chap over the road had been telling me about a BSA his brother has had sitting in his shed for 30 years. The stuff that dreams are made of!! Anyway it turned out to be a Tracker, formerly an NVT Rambler, built in the death throes of the British bike industry in the late 70's. It uses a BSA monoshock frame, Yamaha engine and electrics and Italian suspension and wheels. So at least the engine should be ok!