Topic: CB550K "Clunky" Transmission

[Fuser]

Apologies if this is the wrong subforum for a technical problem; I am posting from a mobile device.

Anyway, my 1974 CB550 Four recently started acting odd. The transmission is clunky (makes the sound of a horse trotting) in first gear, and shifting into second. Beyond that, I can't hear much, but I can still feel some clunking, even shifting into 5th. The bike also shifts into neutral at times, usually from 1st to 2nd, even when I give the shifter a good strong lift.

Thinking it's got something to do with the chain, which is original and a bit rusty.
First noticed it after I shifted too quickly into 5th, and felt/heard a dull snap.

Any suggestions?

[Deltarider]

Adjust drive chain (after lubing).

[Fuser]

Thanks very much, I will give it a shot.

[TwoTired]

Some chains are so rusty they don't bend very easy.  Sometimes a lube makes them flexible again.  But if not, it needs replacement.

If the sprockets are worn, the chain can "ride up" the sprocket tooth, make contact with, and even break a metal guide.  Noise ensues.

Remove the sprocket cover and have a look.