Sounds like the right cylinder isn't running at idle, or running much slower than the left. Not firing at all would be an ignition problem. Running much slower would be a carb sync problem.
The type D cam chain tensioner you have is the worst of the lot, lol, because it doesn't have a lock nut. Yamaha used it for only a few years then went back to one with a lock nut.
The type D cam chain tensioner you have is the worst of the lot, lol, because it doesn't have a lock nut. Yamaha used it for only a few years then went back to one with a lock nut.