Got a 44 tooth sprocket.. but ..

You should be able to go faster even with a 44 sprocket. Have you got any 4 stroking? If so you won't be able to pull a smaller sprocket.

yeah, unless your weight is really high, you're not getting the right performance

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.

I think the problem lies in your tuning.

I had gotten 42.5 mph on a highly modded motor with 44t once. 10k rpms. Stock should run about 28

49cc's are slower anyway. Even tuned properly with a 44t, you're lucky to hit 30.

This has all been covered multiple times, so here's the short version.

Smaller the sprocket, the faster top speed, by sacrificing low end torque.

Heavy bike + heavy rider= slower speed.

Stock engine torque + smaller sprocket = pedaling uphill.

Smaller sprocket size is relative to what the bike can pull. Experimentation is required.