Topic: Transmission slip or clunk

[Coredozer19]

When I let the clutch out a little hard I feel a grabbing popping clunking feeling. I can only describe it as it feels like the drive chain is slipping on the sprockets. 1973 cb350f  I didn’t replace clutch plates. Any ideas? It feels really unatural.

[kslrr]

It could be a sign of something loose within the clutch assembly, warn shifting forks or engagement lugs on the transmission gears.  I've never heard of the primary chain slipping as it is a HIVO type.

[Coredozer19]

The bike has 5k mikes on it. Nothing appears to be worn in the transmission.

[seanbarney41]

does it happen in all gears or just certain one/s?

[Coredozer19]

All gears. Forgot to mention that the bike has sat for 38 years. Original clutch pack from 73 could slipping clutches cause this

[seanbarney41]

Probably the clutch then...specifically what I don't know

[Coredozer19]

Update. It only does it as you release the clutch. It does not do it when you engine brake and then hit the gas again.

[CBJoe]

Checked Drive Chain for excessive free play? Maybe that and a combination of hardened rear crush drive dampers

[pjlogue]

Check your drive chain for frozen/binding links and make sure it is adjusted and oiled properly then check your clutch for warped plates or glazing and check your clutch springs for sag. It is unlikely to be a primary chain issue.

-P.

[Coredozer19]

Drive chain to the rear wheel is brand new. And tightened properly. If you let the clutch out real nice when shifting it doesn’t do it

[kslrr]

Have you physically inspected the clutch yet?

[Coredozer19]

No. But what am I looking for when I do?

[kslrr]

Loose bolts, cracked basket, clutch springs of different lengths or bent, Bent steel plates, cracked fiber plates, etc.

[Patrick]

If the clutch only slips when you fist put it in gear, and then does not slip when you gun it after you are already in gear, I, personally would look first at my clutch cable. If it is the original cable and it is a little sluggish engaging, that could be your problem. Pull it off and check to see if the cable moves freely and easily in the sleeve. That will produce those symptoms.

Patrick

[PeWe]

My CB750 front sprocket with chain can cause a clunk sound when taking off, especially when turning left at the same time. Sprocket can move sideways as designed to align with rear.
If engine stutter or hesitate due to too rich or lean at low rpm it will sound worse. My bike was like that end of last season and beginning of this. Hondaman clutch mod with extra holes drilled reduced that. I have stock clutch since last year due to more cc and need of all grip it can get