Originally Posted by ocho ninja
I think the main reason their not available in widely accible kits is because of legality issues... Look up the laws in your area and see what they have to say about motorized bicycles
Well, Most of the Chinagirl engines are 66cc so they are illegal in most states too, but there's plenty of them around because of the small investment to purchase one.
The HF engines only recently became popular to motorbike builders, and the domestic tranny builders just haven't caught up. The weak economy is also having an effect. Not as many people willing to spend the money it would cost for a reliable HF enfine/ tranny kit deters innovators from tying up money and risk to produce them.