Pinging

[Dusaki]

So the bike is up and running. Starts right up and idles around 1500. I have noticed that when I am under heavy acceleration the engine tends to ping around the 4500-5000 mark. I am running 94 octane fuel. Could this be a timing issue? Or am I running a bit lean on the mixture?

Also, I have notice when I'm deccelerating the bike tends to lurch until I downshift and the rpms raise. The bike has a set of chambers on it along with the stock airbox with K&N filters. I didn't write down the jet sizes, but I'm pretty sure they are stock. The needles are on the second to last groove from the bottom. The air screws are at 1 turn out which smoothed out the low end from the previous setting of 1 1/2 turns.

Does anyone have a jet size I should be looking for with these mods done?

Thanks

[Barry S.]

You should probably have 1 or 2 sizes larger main jet than stock and all 3 the same with chambers, the center one may be one size smaller than the other 2 stock.. These old 2-strokers surge when decelerating, may not be a problem.

[Dusaki]

Thanks for the help.

[Coyote]

I'd say you are lean. The surging snd pinging may minimize when you fatten it up some (larger jets). I would say +1 on the pilots as well as +1 / +2 on the mains. What do the plugs look like?

[Craig380]

I'd check the timing as well, just to be sure. Every bike varies but my own triple pinged at 4-5000rpm when the timing was set to the factory spec. Backing the timing off a little (about 3 degrees or around 0.25mm with a dial gauge) sorted it without any impact on performance.

[Dusaki]

I really appreciate the help guys. Is there a source for jets?

[Coyote]

http://www.sudco.com" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false; ------ or if your local independant bike shop handles Tucker Rocky, he can order them in for you. I have gotten several and they are genuine Mikuni.