Wake up your Huasheng 142F

That's one approach that works. Then you weld a threaded pipe collar on your header so you can swap out kit mufflers for the standard Briggs and Stratton cylinder muffler that lots of guys use. The poo poo pipe that's on my bike now came threaded. The header has a large nut on it so you simply bolt the muffler up to the header and you're good to go. If you don't want to mess with the welding, you can get a 50cc canister muffler for a Honda, or scooter that clamps on. Some fairly good ones are sold on Ebay in the $30 price range. They even have carbon fiber ones that save a little weight.

I was going to put a Supertrapp on this build, but decided that would be overkill for a MB. I went instead with a Phantom custom pipe and I'm glad I did. It came in today with a nice billet aluminum cap,an aluminum mounting clamp, and its wrapped in beige insulation to prevent leg burn. It is a glass packed pipe and it has that "cherry bomb" sound to it. It screams, "Hey, I'm having fun", not "hey, I'm obnoxious". The pipe fit fine with a SBP shift kit and it looks great. Well worth the substantial price. Took the bike out for a quick spin around the neighborhood and love the way it sounds and the way it performs. This is not your typical single speed ride. I strongly endorse the upgrade to the air filter, the bigger jet, and the minimally restrictive pipe. Most important is the ability to shift. All you really need is three gears. What's next? I've ordered a metal locking tool kit that I'll be installing in a couple of days.