The engine is from a racebike 750cc spec unknown.
The 5 speed Quaife is fully rebuilt
Front end will be Commando length forks as the headstock length is longer than the Featherbed & used a special Jim Lee cast iron dropped down top yoke. I have a Norvil front end caliper & disc. The rear wheel is a Triumph conical which I have a Don Pender finned job to make it look like the Manx rear wheel it should be. The tank has patina ie it's well dinged.
The rubber mounts for the engine are actually featherbed swinging arm bushes.
When I strip the frame I probably wont find any clues as Jim didnt number his frames but it is a well worn warhorse. I've made no progress with finding any history on this frame
However
I have through a lovely gentleman called John, traced the whereabouts of the Mick Grant Jim Lee Commando. It is the green bike in the earlier Photo. John says it hasn't been on track since the 80s & is in poor condition. The bike went from Mick to Eric Houston (April 72) then via Alan Duffus, Jack Gow & Stuart Adam's to the current owner.