ORIGINAL: OliverJacob
I think the starter was the problem, I never got the engine to start, I think it was running too slow.
Now I have build a much powerful gear starter which works flawless on a 50 CC engine.
With a new bearing I should be able to start it.
I should have the tools to change the bearing, I would give it a try before I buy a whole clutch.
A poor starter that turns too slowly, will certainly be hard on that bearing and damage it very quickly. Also if you are using a geared starter that "pounds" like osme do, you will find ythat also is hard on the bearing.
Unfortunately, due to the press fit, I do not think they sell the bearing on its own.