bpatton said:
David,
How long has it been pinging? Was it fine before the new rotor? I checked the timing marks on my bike a few years ago and they were about 8 degrees off. Don't know if it was the rotor or the markings on the scale. Just out of curiosity, what cam are you running and when is the pinging happening? Lower revs under load? WOT, on the mains? I skimmed a head once on my 850 to get 10:1 and got some serious pinging, the engine was otherwise stock. I was told that I was asking for it running that high a CR with the mild cam. I changed it for some thing hotter and the pinging went away at low revs. Has to do with the overlap or something. They do sing when they come on the cam. BTW, this was when gas was of a generally higher quality.
Hi Bob
It's been pinging off and on for the last couple of years. Got worse at the end of last season. Original combat cam and combat spec on the engine. Mechanically it's in excellent condition. Just checked the timing mark/scale with a timing wheel on the cam. It matches perfectly. I'm going for race gas next and start blending with 91 octane unleaded/ethanol until I find a good mix. I'd rather go to the trouble with special fuel than give up the combat performance. Good thing I don't rely on it for transportation.
I see some going to small mains, however the cure for pinging is going larger to richen the mixture, cooler flame. If I'm wrong someone sign in.
Thanks,