Originally Posted by biknut
2 stroke China Girl is definitely the way to go on a motor bicycle with these conditions,
1. You have blue print your motor before installation in the frame
2. or, you need to plan on buying about 5 motors on average it get 1 good one out of the box. Still not as bad a deal as it might seem, because you'll have spare parts to keep you going for years.
The advantage of a China Girl as I've described is, it will be faster and lighter, plus just as smooth, and dependable as a 4 stroke of equal size. Even if it's not faster it will still be a lot lighter. China Girl motors are easier to work on, and less maintenance intensive. There's a better aftermarket for China Girl parts, and performance.
When all these considerations are taken into account, the China Girl advantage is pretty much insurmountable.
I must be right because my wife said something about me knowing it, and it all lol.
Another problem with 4 strokes, and this is a deal breaker for me, is most of the common 4 stroke motorized bicycle kits only have a centrifugal clutch. That may not be as much of a problem if you come from a non motorcycle, or non riding background though.