that as i unda stand is 4strokin...i jus back off the throttle and adjust the choke till it goes away.....these are finicky lil pos'....but oh so much funoh and what does 4 stroking sound like sometimes at full at almost full throttle it changes sounds and kinda falls on its face like it has no more power
the last one is a vid if you click on it and that is the best the phone will do the pics suck the most the vid is a little clearer