I thought it was the carb needle not completely engaging (up and down) but i was wrong, checking the spark arrestor to see if its clogged, its a 2008 never been cleaned. Gonna check the valves, air box filter which is new, checking the coil also...it idles perfect, but when i put it in gear won't go over 10 mph, will rev to 2200 rpms not any higher in neutral. doesnt miss or shudder.