
As the rest of the engine didn't show similar symptoms of drastic wear I was curious as to why this might be. I think I found the answer when I checked the valve springs. In the photo below the middle pair of springs are what came out of the bike - these are much longer than specified. A set of new springs of the correct length are the two outside springs. Is it plausible that valve springs that are too long and too strong could cause the rapid wear seen above?