Re: bicycle engine
I have the boy go fast one and the engine is the new one (they claim) with the bearings but the other things the throttle and clutch lever were not very good but hey it was cheap. As for the engine itself, I'm not sure that there is a lot difference in the newer kits. there seem to have been two designs. The older one with the bushing instead of bearings and the new one with the yappanese bearings.
I think the engines are so simple that they are pretty much the same to be honest.
My posts have entertainment value only. A bike ain't yours till it has your blood on it. Then it owns you.