xs400 Maxim Compression Issues

[oldschoolorange]

So you know that your rings are not in the best shape on the left side as the pressure changed by 30 psi when you put in oil. As for your right side I would suspect a top end issue probably a valve hung up on something. If that is the case then it might be a good idea to look for a used engine to put in the thing or rebuild a good used one and then you will not have any problems. As someone who has restored some older bikes I find it best to redo everything that way you can ride and enjoy the thing instead of just doing enough to get you on teh road and having to messs with it constantly