I have a 12A w/ Dellorto side draft. We've been trying to get it running right by working with the timing. Currently, it starts and idles fine, and under medium load its ok. But it breaks up at steady throttle and makes an unfamiliar sound under heavy throttle/load which maybe the ping I read references to in other posts.

 

Pull the exhaust manifold and turn the engine until you can stick your finger in and feel the Apex seals. See if they feel chipped or really rough. They should feel smooth.

 

does it smoke right before or during this noise?

my gsl-se used to ping all the time, it was way too lean, try richening up the top end



mike

 

a ping kinda sounds like a soda can half full being flicked with a pen.

 

The sound can range from a sharp metallic ping, like hitting steel with a hammer to the sound of popcorn popping to rain on a tin roof.



Too rich - mushy throttle response, a wet droning exhaust note, and it will run better when cold than warm.



Too lean - rpm's will hang for a second when letting off the throttle, the exhaust note will be sharp, the engine may surge and buck, and it will run better when hot than cold.