I had a similar thing happen to my nc35, where if i turned the wheel it would clunk and you could feel it through the chain/swingarm. I did what Magg said, remove chain + sprockets and check output shaft. Put new chain and sprockets on and redid chain slack and it disappeared.

Another thing is greasing up the front sprocket with moly grease, takes up a surprising amount of slack..

Hey guys,

This morning I took the front sprocket off to have direct access to the gearbox output shaft and turned it in neutral.
There was no play side to side and it spun with zero notches/clunks...very smooth.
Would I feel a problem with the bearings just spinning/turning the shaft by hand or could there still be a problem with the bearings but only when under tension from the chain?

Thanks.

You would feel it by hand i think, make sure that the shaft is straight too - just turn it and watch if it walks off center.

Thanks, I'll check how straight it is.

Next on the list is to check the chain and rear sprocket.

If ok on that side then check the clutch side the small outer bearing the nut staked tight the basket itself plates etc and as i said before any movement on the shaft itself as the double bearing can fail .

Rear hub bearings ok ?

Thanks Dynamohum,

I've never had the clutch basket off so what holds it in place? I know I need to check to see if it wobbles and how badly it is worn/scored.
I'll check to see all plates aren't warped and are the correct thickness along with any obvious scoring/bluing etc.

I presume I check the shaft for play, feeling exactly the same as the output shaft.... if the bearing has gone inside, what entry point do I put a homemade bearing puller into?

Going to check the rear hun bearings too, thanks. Not sure how though? Lol

The rear hub bearings could be checked by grabbing the wheel looking for movement spinning the hub by hand feeling for any roughness in bearings within or removing the large hub nut take out shaft clean regrease and check the bearings that way.
Re the large bearing on the clutch basket side the basket comes out after removing the starter gear and oil pump chain then the basket slides of the splined shaft you might need an impact gun to get the bolt in the starter gear off though.
The large bearing has a retainer plate then you would need to fashion some kind of puller to pull bearing out i got a mechanic to remove mine and replace .
If you can get any kind of movement up down sideways on basket and shaft chances are that bearing is the culprit however eliminate any other any other problems drive side first.
Its not unknown for that bearing to fail on nc30/35 do a search .

Symptoms i had was a noise with clutch in and a shudder vibration and horrible noise that could be felt through the clutch lever and pegs when pulling away if that helps .