There are plenty of people racing these Chonda 6HP in go karts. There are step by step how to's on the net to take you through giving them more grunt including replacing cams, changing valves etc. One of the first things is, take it apart and throw away the governor and use a manual throttle. Of course you have to limit the RPM but according to the race boys if you do the work using performance parts you can easily rev the little suckers out to 6000 RPM or more.
