Topic: CB125s Transmission noise

[Leanier]

I have a friend with 1975 CB125s that is making some odd transmission noises..  Its a clunk click like sound that happens in a defined spot on the front sprocket shaft.  Seems to be from inside the engine.  Any ideas? Seems odd it would make one defined spot if it was tranny gears, that should be a solid grind, this is only in one spot on the shaft.  Also, its quiet when the bike is cold, and gets progressively louder as it warms up, probably as things expand.  It seems to change when messing around with the gears, but it never goes away, and is definitely on the output shaft as it doesn't change timing or anything with gears.

[grcamna2]

Does it make the sounds while in neutral ? or does it have to be in a gear ?

[Leanier]

Any gear and neutral, pretty much anytime.  Sometimes when messing with shifting it randomly goes away, then comes back, with no pattern.

[grcamna2]

I would pull off the R.side(clutch)engine cover and check you're clutch/clutch basket assembly before anything else;have a look behind there and remove the spark plug & put the cycle up on the centerstand(if it still has one)and put it in 4th or 5th gear and try turning the rear wheel over and spinning the engine..while you observe the action around the clutch basket and listen to it's operation.