The Supermono was a bit of a (for the time) technical tour de force, IIRC it was Massimo Bordi who thought of the idea to use the now redundant crank pin to attach a small 'conrod' to it for use as a balance shaft, when the rear cylinder was lopped off. Which saved a costly redesign of the crankcases, and nullified the single's inherent balance and vibration issues. They rev to unheard of rpm for a 4T single. Sir Al Cathcart raced one at Bathurst they fetch big bucks now.