Aren't you the guy that almost got an aneurysm because you had trouble tuning your carburetor to run right? I think that is your problem, a stock motor can push you to 30 mph, but I remember reading your other thread you said you were over 200 pounds? Even still at that weight, I think you should be going faster than just 20 mph. I don't weight nearly as much, but you know how they sometimes have an electronic board near a school that shows you how fast you are running through a school zone? I wasn't even going full throttle and it was showing 28 mph........ and don't worry, school was out.