But if i let it return to idle then slam it it will go no problem. It revs up to onlly 4-5 thousand then i have to let off the throttle then hit it againand itll go. Ive cleaned the carbs, tuned them, ran new oil and gas lines. Also have brand new head gaskets and changed the filters. It doesnt smoke up and runs great it just has this stumble everynow and then.