Burnt Valve
- Thread starter bmetcalf
- Start date
One wiseguy suggested the screwdriver in the pic got sucked in.
Since this was brought to light, I have heard it happened to a 60's Triumph and a '96 BMW twin. Steve Hamel has put a Terry Prince valve in and declared the guide OK. The piece of valve rim broke off when he was tapping the stem through the collar. The break was across a 1/8" square section! I was yards away from a lot more money to repair things!
I had the front exh valve out and it was in very good shape, so I just have to whip the heads back on and ride it.
I am convinced that the valve had a flaw and caused the failure, the colors of piston, plug, etc. all looked good.
Since this was brought to light, I have heard it happened to a 60's Triumph and a '96 BMW twin. Steve Hamel has put a Terry Prince valve in and declared the guide OK. The piece of valve rim broke off when he was tapping the stem through the collar. The break was across a 1/8" square section! I was yards away from a lot more money to repair things!
I had the front exh valve out and it was in very good shape, so I just have to whip the heads back on and ride it.
I am convinced that the valve had a flaw and caused the failure, the colors of piston, plug, etc. all looked good.
Another myth: high octane fuel in a Vincent is merely a waste of money. It does neither damage not good. It MAY put some lead on the seats. I've used the occasional tank of Avgas in the Vin, which made not a blind bit of difference either way. At 7.3:1 Avgas's anti-knock properties remained unused. I guess you had a duff valve. QUOTE=Bracker1;24901]Reference MPH 449, an article by J.Bradshaw with regards to too high fuel octane with low compression engines as well as the use of oils that allow "coke" build-up in the valve area. Or could just be a soft spot in the valve. Mine looked the same, and I had Steve Hamel put some fancy ones in. Good Luck, Dan[/QUOTE]
Steve H. knows what to do. I didn't realize he is was a celebrity until a fellow showed me his write-up in a book about dream garages. Nice article. My bike's value just went up. On the topic of burnt valves, if I remember right, P. Irving wrote about the ill affects of overtightening the head bolts and causing a cascade of engine damage including burnt valves. Go figure something as simple as tightening a bolt can cause so much trouble. Hope to see everyone at the International. Dan