I would be interested hearing issues involve with installing the 2-cycle motors from china, on mountain bike frames. things like dealing with the de-railer, hand brakes,fat frames,etc. Also, the wheel configurations that aren't bolted solidly to the frame, but rather have quick connections. I also received a throttle cable that was to short where as the only way it would fit left the slide in the carb barrel fully open. I had to cut the cable outer sleeve back about 2 inches and I think I'll still have to cut it back some more. Is there any quality control at all in China?

qc, would mean they check it to make sure it works. or that it doesn't explode.
qc will not determine if it fits your bike, seeing as there are hundereds upon hundreds of different configurations and blah blah blah. They also say it may or may not fit your bike, and also provide a diagram to measure against. qc. won't ever solve your type of problem.