you want to build something that will beat any L/C china bike, and even most L/C euro's? get a BZM 50cc AC kit, a sylver plate racing crank, BZM 3 pad carbonium clutch, Zocchi clutch housing, a genuine phgb 19mm Del'orto carb, Polini fiberglass reeds, BZM Junior racing pipe. I've seen this setup in a Stamas Techno frame, freaking monster, comes with the price, and the time and effort you need to get it running at it's prime, but it is and probably will remain the fastest air cooled pocket bike I have seen.
Here's a pic http://img27.xooimage.com/views/8/b/9/100_2995-15a37b0.jpg/
Here's a pic http://img27.xooimage.com/views/8/b/9/100_2995-15a37b0.jpg/
