Yes the Guareschi brothers kit. It's very nice but have a think. You are taking an engine, transmission and final drive that is totally unsuited to a cutting edge pointy ended sports motorcycle and creating something thats trying to be just that. It's wheelbase is too long by a mile, its way to heavy, its an across the frame V twin, its not water cooled. I like the engine and drive system just fine but you're wasting your time using it in this context. Its natural element is in a GT style road bike. A Griso is about as close to a "sports bike" as this engine , gearbox and drive line should be to a cutting edge sports bike/track orientated tool.
Ciao