Rear sprocket floating?
 

Hello ,

I just notced that the rear sprocket is floating slightly (I recently replaced the chain and sprockets) along the axis of the axle. It isnt obvious to me that this is wrong, and I cant recall if it has always been like that. I have however done some 2200 miles since I changed the sprockets etc.

So is there a problem (if so any ideas what the cause could be?), or is this normal?

Thanks

Douglas

I replaced my rear sprocket with a Renthal carrier and 40T sprocket. I also have a bit of lateral movement along the axle. Asked about it come service time and was told it wasn't an issue (I also raised the point during the MOT - it only becomes an issue if the cush drives wear enough to foul the swingarm).

The bike has done 4k miles with the sprocket and never had any problems with it.

Hope this helps

Best to post what type of bike it is? Then you may get more replies.:D

Its a 1998 748 Bip!

Oh, and I have had a careful look, and nothing seems to be fouling the hub, or grinding metal off the swing arm or hub.

Is the sprocket moving? or the sprocket carrier? How much movement is there?

The sprocket is moving on the carrier. I would say about 10 - 20 thou at the most

Correct me if i'm wrong but there should be some nominal amount of play due to the cush drive.

But i'll check mym bike to see if i have the same.

The rear of the sprocket/renthal carrier is held in place by a large circlip.
This steel circlip in its groove on the ali sprocket centre tends to gradually wear the groove wider and wider and this lets the carrier/sprocket float a bit.
My 1997 916 Bip did this after about 40,000 miles.

I replaced it with the later 996 type which has a different ali centre and a separate spacer to prevent any rearward movement. No circlip -no wear.

If you have got a mate with access to a lathe/machine shop you may be able to shorten the old worn ali centre and turn up a spacer to go with it.

All you need are the dimensions from someone with a later model who is prepared to strip and measure it.

If you get the measurements let me know because my 98 916 will need doing sometime.

Steve B

See Eccentric hub problem thread, it is explained better than I did.
Could have saved myself some typing if I had seen that one first.

Steve B

Hi
I removed the sprocket and carrier over the weekend. All was well in the circlip/carrier area, but the sprocket was moving on the carrier. When I removed the sprocket I noticed that the cush drives were a very slack fit in the sprocket, and there was some lateral play on the sprocket too.

The new sprocket came from B&C Express, in one of their chain and sprocket kits that everyone on here speaks so well of. I noticed that the old sprocket was a much more snug fit in the cush drives.

I have removed some of the lateral play by fitting washers behind the cush drive nuts, although the sprocket can still move to accomodate the cush effect. The result is there is still a little play on the sprocket in both planes, but it is much better.

I have noticed on the couple of bikes Ive seen recently that they have no play, so I am still not sure if my set up is right. Does anyone have any experience of replacement sprockets being a bit sloppy in the cush drive area?

Hi Douglas

Mine is exactly the same (albeit S4R) - very slight "play", and have been advised by a dealer here that its ok. I checked a mates 998 and his didn't do it but have seen several 748's / S4R's/ 916's that do.
Hope that offers a little reassurance.
Cheers

Johnny

Thanks, yes that does make me feel re assured!

Douglas