The bearings of the AX have little to do with the power of the engine. It has more to do with the timing of the crank and sleeve, and the higher flow of the carb.

Nothing inherently wrong with plain bearing engines. The engine in every car on the road uses them.

For beginners, they are much easier to clean when you make contact with the ground. Nobody plans on crashing a lot, but it does happen.

One thing about plain bearing engines, they do need fuel with slightly more oil.