I have a Renthal sprocket carrier fitted to my 996, which I did to avoid the chance of the dreaded cush-drive-rubbing-hub problem. Well Ive just noticed very fine metalic particles around the hub and discovered that the carrier/sprocket assembly is moving from side to side (approx.3mm play) on the cush drives and is touching the hub. No major wear yet but something is not right. Does this mean that a washer or collar is missing?
I had this happen on my 916 despite the cush drives being fine. The big circlip groove in the sprocket carrier had worn away so that the whole assembly moved in. Best fix is a later type type carrier (998) which does away with the circlip and uses a tapered spacer instead, although you can machine down the carrier and just buy (or make) the tapered part to save some money.
Oh God I thought I was safe with the Renthal. Now there's something else I've gotta keep an eye on. Thanks for the posts guys. Hope you sort it mate.
Thanks for the reply Duke. Is the circlip groove in the Renthal part or the duc 'sprocket flange' (as called in parts manual). I can't inspect it as I don't have the socket & 10ft scaffolding bar to remove the big nut, or the fat b'stard to sit on the bike while I do it. I had the new sprocket and Ren. carrier fitted at a dealer just a few months ago. I've had another look at it and the castellated adjuster of the hub doesn't seem worn at all. I don't think the edges of the Renthal carrier are actually touching it, although it is bloody close. I'm not sure where the metalic shaving have come from, poss the circlip groove? I'm going to take it in to where it was fitted and have them check it out.
Yeah, me too! And I've got a slow puncture in the front. I think it's losing air in sympathy with what's going on at rear end...
The circlip groove is in the Ducati flange part with the cush drive bobbins attached, the circlip holds the renthal carrier on to that
These pics should help; Old style carrier with knackered circlip groove; New type 2-piece carrier with conical spacer to replace circlip; Spacer; You can get both parts or just machine the old type carrier down to the steel bush and then buy (or make) just the spacer. This new type completely resolves the problem...
Update on this....I finally removed the flange and sprocket carrier assembly and took a good look at it. The circlip groove doesn't look worn at all - all the wear is on the Renthal carrier and the hub, and the reason is because the big washer that was supposed to be between the carrier and the circlip was missing, allowing the carrier/sprocket to move in enough to touch the hub. The play must've been there from the day the Renthal carrier was fitted. I ordered the new style flange and bush but now realise that I didn't need to - all I needed was the feckin washer. Grrrr. And I've lost a whole bank holiday weekend of riding because I was daft enough to allow a so called expert to do it. Again. Fortunately the wear is minimal and wouldn't have got any worse as the flange face was up against the steel washer on the spindle, but still. Aside..I don't see how the circlip groove could wear as there is no movement between those parts.
Neither do I but mine wore so much that the sprocket machined the hub until there was barely enough to get the adjuster tool onto (then later a popped cush drive finished the job). If you've ordered the new type and it's too late to cancel then I'd fit it anyway and prevent the problem from happening.
I suppose the circlip, once loose, will spin about with its own momentum and wear the groove. The part I ordered has just arrived...and it's the wrong bloody style! They've sent a circlip style flange with the conical spacer. And it's clearly been used. FFS, can't anyone do a soddin job properly out there?!
Personally I'd keep the conical spacer, send back the carrier and then machine my carrier (cut the alloy off down to the steel bush) and use that - it's the same as the new part but significantly cheaper.
Not sure if it helps. But I was told the other day JT do carriers for the Duc's now. Supposed to be pretty good.
