Politicians have destroyed the market for Whizzers in several states where they have to be registered as a motorcycle because of displacement. Riders figure they might as well just buy a motorcycle with more features, a modern engine design, and a transmission. I sold mine when the state tightened requirements for motorized bicycles, Instead, I started making Whizzer-type bikes that meet the 50cc requirement. There has never been a liberty in history that politicians didn't want to trample. Aside from that, you got the deal of a lifetime. The best thing you can do to get the most out of both bikes is to make sure they are properly tuned and make sure your belts aren't slipping. When I got those things right, my ole Whizzer would easily do 40-45 MPH and on a good day I could outrun my buddy's Cushman! I think Wrench gets higher speeds from his Whizzer. I'm currently tinkering with the jetting on a Huasheng with a Keihin carb. Assuming your bike has the same 19mm Keihin, there is a wide range of jets available if you want to de-restrict the air filter and exhaust.