Re: Chain jumps off what to do?????
Welcome, make sure the engine is mounted solid to the frame without any movement whatever. Then install the chain and tighten it so that it has about 1/2 movement on the top or return chain, then hold or lock in the clutch and roll the bike watching the chain as it rides over the tensioner. If it runs inthe center of the tensioner that's good if not roll it backwards and see if it moves to the other side of the tensioner, if so you wil either align the tensioner or bend it slightly to make the chain roll over straight. It takes some time to wear off the rough edges of some sprockets , just keep an eye on the tightness and alignment. Good luck
Your results may not be the same,Greg