Still hunting down noise

[nulldevice]

My scooter,s honda clone motor has a very loud scrape/rattle/crunching noise, like a bad bearing, but it doesn't have the deep down knock a crank or rod bearing has.

I eliminated the drive train by simply removing the variator and clutch assemblies and starting the motor. The noise was still there. Possible back break rattle was eliminated by squeezing the rear brake handle.

I changed the motor oil and there were no visible metal fragments.

It doesn't sound like a loose cam chain, it seems centered low on the right side and the adjustment is automatic any how.

Turning the motor with the variator nut showed no roughness.

Is it the one way starting clutch I hear?

[OverReved]

Possible crank bearing failure. You can give the end of the crank on both sides a good wiggle and see the problem if it is. The noise with bad crank bearings isn't rhythmic and can come and go. It's only going to get worse if so. The cage holding the balls evenly spaced may have broken, there'll be no metallic shavings etc till you've put quite a bit of run time on it.

[richardthescooter1]

Did you change the gear oil Could be low in gear oil