I have an 86 VF500 with a blown gasket. When I pulled the head off, I found a couple of things. First, their was a dowel pin missing on 1 side. Could this cause the gasket to fail? Second, The chain tensioner long piece was broke at the pivot point. Haven't found any metal pieces and cyclinder is in good shape. What kind of damage might this have caused? I am having a copper gasket made up, working with the guy from Coppergaskets.
Boy, it's hard to say for sure. The fact that parts were missing/broken tells me that 1) it's been apart before and 2) someone did a poor job. My guess is that it's the PO's fault and not yours (or the bike's).
I don't understand how you could not use the dowel pin, or replace if missing. It only cost a couple of bucks. I am waiting on my gasket. Head appears not to be warped, but I might have it shaved anyways while I wait. Would the broken arm of the tensioner cause the gasket to fail or just allow the chain to run loose, probably making a loud noise. I got the bike in this condition. Trying to get it back up and running. Thanks for all the info you guys provide.