Topic: rear sprocket wobble

[gto_ron]

This may be an old topic but it's new to me.

On my 750K the back rim runout is well within spec.  The sprocket was torqued in a star pattern with new tongue washers.  The rear sprocket wobbles enough that I'm not going to ride it until I figure out what's wrong.   What can be the problem?  Running the bike on the center stand, I can hear the chain bind each revolution.   They are new sprockets and chain. Any advice appreciated. 


regards

Ron

[goldarrow]

I had a similar situation on my bike, but old chain and sprocket.  I loosened the chain adjustment and slack them a bit, then lubed the chain.  The wheel seem to spin freely now. 

[ekpent]

Sprocket carrier is seated well and even around the outside edges to the hub ??.   There are rubber dampers in there that can possibly cause a wedge on the fit. Axle tight and aligned correctly ? Other than that make sure the new sprockets not bent.

[Grabcon]

I agree with check the cush drive, but I would remove the sprocket, clean it, put it on a flat surface and check for flatness. I typically use the cast iron table on my table saw or a piece of granite counter top. check for rocking on both sides and use a feeler gauge to check as well.

[Cqyqte]

As well when the sprocket is off put the wheel back in the swing arm and measure runout of the sprocket mounting surface on the hub.  That will tell you if you have an issue with the cushdrive fitment.  Also check the sprocket thickness in several locations I have seen them out significantly, a result of the lathe operator when the sprocket faces were machined.

[Raul CB750K1]

Can't remember on the 750, but on the 350 the sprocket is retained in the hub with a circlip washer, avoiding any side movement.

[Cqyqte]

No the Sprocket bolts to a carrier that holds the bearing and the carrier fits into the rubber slots of the cushdrive.  If the bearing in the carrier is not driven squarely into the carrier the retaining face for the sprocket can and will have unacceptable runout causing what he is describing.  A small amount will multiply dramatically once you measure the outer edges of the rear sprocket.  Thats why I suggested he reinstall everything without the sprocket and check the retaining face for runout.

[Jerry Rxman Griffin aka MuthaF'er]

Possibly bent by tightening the chain incorrectly?