Yesterday my bike stopped running while I was driving. I couldn't get it started again but sometimes it started running again but couldn't get higher in revs and stopped running when loosening the throttle. Back home I started checking the gasflow, carburettor and ignition. I noticed the flightwheel didn't spin in a nice straight way so I took it off checking the woodruff key holding the flightwheel in place. The woodruff key was broken and deformed from being battered between the flightwheel and the crankshaft. As a result the little whole in the crankshaft keeping it in place got deformed badly. I'm afraid I'm going to need a new crankshaft. Can anyone please confirm this? The woodruff key now doesn't sit as tight as it should be.