S2R front sprocket pinion fixing plate P/N 82610111A

[skurvy]

The Parts Manual refers to it as the "Sprocket Keep Plate". I'm not sure why I'm starting to chew these up.

'06 S2R, 44k miles on it. Never had a problem with the stock part, it seemed to last around 30k miles. I did the 14T front sprocket change when it was time to replace the original chain/sprockets. Switched to a 520 setup with a Super Stealth rear sprocket, DID ERV3, and I think a JT front sprocket. I noticed a lot of chain noise at around 35k and was ready to replace it all again but when I saw the front sprocket, I was surprised to see that front plate all chewed up. So I replaced the plate and it lasted maybe another 7k miles.

My last chain and sprocket change was maybe at 42k? (All new parts). I'm keeping a close eye on it but I know something's gotta be out of whack. I've brought it to the 2 Ducati dealers near me and they both can't find anything out of spec. Chain adjustment is not too tight, I clean and lube the chain every 2 weeks or so with DuPont Teflon Chain-Saver (yellow can).

What else can I check?




I pushed the sprocket inward a little to show the wear on the splines on the shaft:


Left to Right: New plate, wear after 7k miles, Original part changed at 35k:

[brad black]

the original parts was completely rooted and left on there way too long and damaged the output shaft that is now damaging any new plate you put on it.

that's my take anyway.

[skurvy]

thanks brad black, you're absolutely right. The damage is already done. I guess the only way to fix it is to replace the shaft $$$. I looked up the part (P/N 14910341A) and it's about $350. I don't have the tools or the means to tear down the motor myself, I'm sure that ain't gonna be cheap. 

My only option right now is save up to fix it the right way and keep doing the band-aid fix, changing out the plates from time to time. The plates cost $9 each.

Let me ask you this, if I'm eventually going to change the output shaft, is there anything else worth upgrading while it's apart?

[brad black]

Let me ask you this, if I'm eventually going to change the output shaft, is there anything else worth upgrading while it's apart?

how much money do you have?

[skurvy]

how much money do you have?

yeah saw that coming...  I guess the answer right now is "not much". I'll have to stick with replacing the plates every now and then. The sprocket (hopefully) won't fly off since the splines aren't damaged on the side facing out. I just hope the wear on the inner side doesn't get too dangerous. I'm not aggressive on the bike, but I do commute at least 250 miles a week.

Talking to the shop, they guess-timated 15-20 hours to R&R the shaft.

[Speeddog]

You can cut down an old sprocket (both width and diameter) to act as a spacer on the inside.
The sprocket/spacer splines will bottom out in the spline runout on the shaft.
A simple cylindrical spacer on the outer end, long enough to come up flush with the end of the shaft.
Then a husky flat washer under an 8mm bolt in the end of the shaft.

Everything sized such that the sprocket can still float a bit.

AFAIK, there was an inner spacer manufactured at some point, as the ST2's seemed to have this affliction more than most.

[skurvy]

Update:

So replacing the keeper plate sounded like a good idea and seems to be working although I'm changing them at sooner intervals. They seem to last about 2500 miles now. I'm sure the splines have worn more causing any new plates to deteriorate even quicker. I called DNA and they had never heard of anyone having this problem and had no idea about any spacer for the ST2s. I asked the guy if replacing the keeper plates was ok for the time being, and he just kept answering, "What did the Ducati dealer say?". I understand those calls are recorded and he didn't want to be liable for telling me it was ok to do the band aid fix.

I don't know any metal shops in my area that would shave down another sprocket to make the spacer and I'm about to hit 50,000 miles, I'm averaging 1,000 miles a month. I'm about to put it in the shop to replace the timing belts again and replace the clutch master cylinder. (Rubber seal on the master has dry rotted and will replace with new part from Yoyodyne). I was contemplating switching to a 16 RCS setup but decided against it because I'd have to get a new reservoir, mirror mount, etc... I guess it would be kinda dumb having that on the clutch side and a stock brake setup on the other side.

Back to the point. I don't think I can bring myself to sell the S2R to get a beater commuter car. i love riding too much. Even the crappy days in the rain and all the f'd up drivers texting and talking.

To those with higher mileage experience: IF I bite the bullet and replace the shaft, what would be the next thing to consider while the motor is ripped apart? I really don't think the shop I'm bringing it to can fabricate a spacer for me. I'm guessing doing this fix with the timing belt service...all in all about $3000. Probably more than my bike is worth...

[brad black]

the sprockets are really hard and impossible to machine ime, but if you got it heat treated to make it soft then it could be done easily.  or just heat it with the oxy till red and drop it in water.

it's much, much better than pulling the engine to split it.  depending on labour rates, i'd say $3k is optimistic.

or just fit a locking plate behind the sprocket at the base of the spline, then space between the plate and sprocket as required to locate the outer locking plate in the groove.  possibly even an aluminium sleeve would work.

and cover everything in heavy anti seize paste.  i like the loctite silver.

[Speeddog]

I dug out the pics from when I did a fix on a friend's ST2 with the same issue.
It wanted to pull the sprocket inboard, so the spacer was the ticket.
I've also seen where the sprocket wants to run outboard off the end of the shaft.

As Brad said, they are quite hard, and will tear up standard cutting tools like lathe tool bits and end mills.
For this job, I used an air-powered 3" abrasive cutoff wheel  and a cheapo tabletop belt sander.

Sacrificial lamb:




Slice off these bits:




Adjust thickness to suit, and finish to more or less round:




Installed:

[clubhousemotorsports]

Why not have a local machine shop make you a new plate that attaches via the screw hole in the end of the output shaft? You could have them make screw holes to locate the sprocket to the plate and then the plate would attach at the end of the shaft. We used to see race bikes with the sprocket held on this way.

[skurvy]

brad black, Speeddog, and clubhousemotorsports:

Thanks for the replies and reassuring me there's more than one way to skin a cat. I spoke to a local race shop that specializes in Ducs and they are seeing if they can fab something up. I think everyone is in agreement that splitting the cases is the last option.

I put a new keeper plate on over the weekend and rode into work this morning- the bike runs perfectly, for now…

I'll let you know what the shop comes back with. Thanks for the info and pics!

[skurvy]

Just wanted to update this thread with pics of the spacer a shop was able to make for me. (I think it's a JT sprocket). I've been using it for 4,000+ miles so far and it's a solid set up. The thickness was shaved down just enough to allow for a little wiggle room but the wear on the keeper plates has stopped.

   

   

   

   




Thanks again for everyone's help! 

[Ducati Jon]

Reviving this thread... This is a great write-up. Thank you! I am having the same issue however my sprocket wants to come off the end of the shaft. I may need to utilize the bolt on the end of the shaft. Has anyone done that yet???

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[Speeddog]

I've not done it.

However it's done, it needs to allow the spacer to float.
If it's solidly bolted to the sprocket, and then solidly pinched by the bolt in the end of the shaft, something's going to come loose, as the sprocket can move a bit on the splines.

A spacer bolted to the sprocket, but retained by a 'top-hat' under the bolt in the end of the shaft.

[Ducati Jon]

Thanks speeddog

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