They send a 112 & 115 main jet with the jet kit from CSC. 112 for stock exhaust and 115 for performance exhaust. I found that it didn't run like it should until I went to a 120 jet and added this easily adjustable air mix screw. So obviously I have the performance exhaust, but it runs amazing right now. 120 jet with air mix screw right at 1 3/4 turns out. The exhaust kit I bought comes with the jet kit and has the correct flange so it bolts right up to the engine. You have to get the 120 jet from Amazon or eBay, same with the screw. About that, the screw is for a Mikuni and doesn't fit, cut a flat head into the fixed air mix screw, cut the red one off and filed it down to a flat head. Then JB Welded it together. It's been the secret to getting the mixture correct and as I said, runs amazing now. (for a 229cc)
Exhaust from:
https://carcustomonline.com/direct-b...al-sport-bike/
**looks like they're no longer making the exhaust for it**