Answer:
I found this on E-How, although it seems some of the important technical information is sadly lacking. Still, it might be enough to get you going in the right direction : http://www.ehow.com/how_2259093_build-gas-scooter.html (copy and paste into browser). Depending on where you live, however, it would probably be less expensive to watch the classifieds, buy one (or 2 or more, for parts to mix and match) on the cheap, and fix it up.