I have pooched my hub on my '06 S2RK for the second time!

[Bonster]

Not having a good evening.  Went to clean my bike after a 400 mile loop that encountered a few thunderstorms in the mountains on Monday.  (I have a new drivetrain - RK 520 chain, Afam sprockets and carrier - that was professionally installed three weeks ago complete with new cush drives, everything looking tight and race wired in.)  I get to the final stage of cleaning (wheels and chain) when I notice one of the sprocket bolts is missing and on closer inspection I see that tell-tale sheared metal where the chain adjustment indents should be.  I have no idea how I rode like this.  Probably because my bike is so noisy with the Termis and open clutch and I was all beat down from a 400 mile canyon rip.

Unfortunately this is a sequel to an old movie.   In 2009 one of the cush drive bushings backed off and ground it's steel edge against the aluminum hub... and introduced me to Ducati replacement part prices .  Dealer quoted me $1750 for the part (swing arm hub and hub damper).  I wound up sourcing one on Ebay for $525 which was obviously a relief, but add a couple hours shop labour and it was not the most gratifying money I've spent on my Monster.

I'm just stunned it's happened again.  My bike has 51,000 kilometers (35,000 miles).  Has this happened to any of you guys?  Is this common? 

It's a bummer.       

[Howie]

I suggest getting the bike back to the shop that did the work in the exact condition it is, yep you want to trailer it or get them to pick it up.  If they pooched it they own the damage.

[ellingly]

Yes, common. Happened to me in 2009, too. I did mine for cheaper than that and I did mine at home. I even replaced the sprocket side bearing in the hub .

... and I wrote up a tutorial on doing it yourself, too.

http://www.ducatimonsterforum.org/index.php?topic=34425.0

[ungeheuer]

... and I wrote up a tutorial on doing it yourself, too.

http://www.ducatimonsterforum.org/index.php?topic=34425.0

One of the finest, most detailed and helpful posts on the board 

Here's hoping I never need it though.

[xcaptainxbloodx]

I suggest getting the bike back to the shop that did the work in the exact condition it is, yep you want to trailer it or get them to pick it up.  If they pooched it they own the damage.

This.

If it was installed by a professional then they should make it right. Shit happens, even to the best. But the best will make it right on their dime.

[Stuka Pilot]

This seems like a real horror story.

What exactly is the root cause of this happening? And probably more to the point what preventative actions can be taken?

[ellingly]

The cush drives separate the center to the outer due to insufficient bonding between the rubber part of the cush drive and the central part which is what bolts it to the hub that drives the rear axle.

From my worklog posted earlier:






To me it looks like they just haven't got the bonding between the central bolt and the rubber down pat. There's been a bunch of revised cush drive part #s which seem to have different rubber materials and maybe bonding so I'm sure it's something they've tried to fix but just haven't got the engineering right on.

The preventative maintenance could be either replacing cush drives really regularly, or fit a sprocket that positively retains the cush drives. I went for a supersprox sprocket that does exactly that, so they can't back out.

If the shop fitted the new rear sprocket and they suddenly backed out I'd be pissed. I missed that in the OP. The shop should really have checked the cush drives before fitting them.

[Bonster]

I started this so guess I should post follow-up.  The mechanic was really cool about it and as the last one to touch it, he owned it.  It's one of those "shit happens" things, but it can be a very costly piece of shit indeed, like $1800 if you just order a new rear hub axle from Ducati.

Anyway, the mechanic was originally going to replace the hub and sprocket carrier with used ones he happened to have lying around, unfortunately the hub he had did not fit (I saw it with my own eyes).  So he replaced the cracked carrier and put it back together so I could ride it, but obviously with the chain adjustment cogs all shaved off the hub I'd have to replace that eventually.  He said he'd try to source me a used one and install it no charge, but a week later I got impatient and just now I ordered a used one off Ebay for $100 and when it gets here I'll get him to install it.  BTW, that's an improvement over the last one I had to buy on Ebay ($500) so I'm thankful for small mercies.

To clarify, the first time it happened back in '09 it was a result of the cush drive backing out as alluded to in other post, and this is a design flaw IMO.  This time it was the result of a nut coming off the sprocket bolt on my new aftermarket Afam and the head of the bolt grinding into the hub.  My advice is be very careful with aftermarket sprockets.  The mechanic replaced all the sprocket bolts with ones with a slightly longer thread and then race wired them.   My cush drives are all race wired in place now too.   The alternative is keep a real close eye on them and how many of you stick your face down there and have a look before every ride to make sure the bushings on the cush drives haven't backed out?    That's what I thought. 

[brad black]

most of the aftermarket carriers have a lip at the back of the bush hole to stop the bush moving in.

but you're saying one of the little screws that hold the sprocket to the carrier caused this?

[Bonster]

Yes.  This time a nut came off, the bolt backed out and was wedged at a 45 degree angle with its head grinding away into the hub.  The end result looks a lot like pics from other poster with nothing much left of the chain adjustment cogs.