1980 KZ550A worth fixing?

Bad tensioner?

Manual cam chain tensioner installed. I turned the engine till the chain went loose and tightened the tensioner down till there was about 1/4" play up or down. Put it back together and MOST of my problems went away. Now Im back where I was a week ago. Starts fine, idles fine, but when revved up past 3500 rpm it is not letting up unless it is shut off. From what Ive read, I would suspect the vacuum hose and vacuum switch?

Are you installing the valve cover after the chain is tensioned?
If you haven't seen it yet, this page explains why you should not do that. It also has better drawings for timing the cams:
home.comcast.net/~loudgpz/GPZweb/CamsKZZ...KZZXZR550500400.html

Your symptoms, now, do sound like vacuum. That should be easy to check using carb cleaner etc.