GY6 cam bearing question

[stuartshomepc]

I've been rebuilding cycle engines for 20+ years but am just getting into these 50cc and 150cc GY6 motors so I'm not sure what is "normal". I've got a 150cc GY6 apart that must have dropped a valve at one time which resulted the the typical marks in the combustion chamber and a cracked camshaft holder. But

The cam end bearing seem "notchy" when you turn it and I'm not sure if that's normal of part of that cam stopper mechanism. So before I ordered the cam I thought that I would ask if that is "normal" or part of that end mechanism. It's not like it's grinding like a bad bearing, but there is resistance when you turn it and then it "clicks" into the next position.

Any help? is that the way it's supposed to be?

Thanks in advance, Stuart

[SYCARMS]

It should spin freely and smoothly, sounds like it may have become burred on either a ball or the race. Try flushing the bearing with pennetrating oil to se if it goes away. There can be trash in it.

TOM

[GX150]

There is a counter rotation mechanism on some cams that make identical sounds (not all of them have this). If you remove the cam and spin the bearings, they should be smooth.