Ducati Monster Forum

Moto Board => Tech => Topic started by: dusty on March 28, 2019, 03:40:52 PM

Title: Shim behind countershaft sprocket
Post by: dusty on March 28, 2019, 03:40:52 PM
Hey guys,

Pulled my sprocket off for some chain maintenance and noticed it's a little wobbly on the countershaft splines. The countershaft itself is steady as a rock, but the sprocket can pitch back and forth a bit (not a drastic amount, but enough that I'm curious) on it. The splines on the sprocket, shaft, and retainer are perfectly fine. I noticed on the parts manual there's a shim that goes behind the sprocket, and there's a thread over on ducati.ms that purports to fix the wobble with this - but frankly I can't see how a ~1mm shim on the backside of the sprocket with no attachment would possibly prevent that sort of wobble? Can anyone weigh in on it, and whether or not they have the shim on their bike/whether they've got wobble?
Title: Re: Shim behind countershaft sprocket
Post by: RB on March 28, 2019, 04:56:05 PM
Someone correct me but I thought it is suppose to wobble a bit or float to cure any small misalignment between the two sprockets. Mine does and I've replaced my front sprocket and retainer.
Title: Re: Shim behind countershaft sprocket
Post by: Speeddog on March 28, 2019, 07:43:46 PM
It will float a little.

We will have trouble defining what "a little" is.
Title: Re: Shim behind countershaft sprocket
Post by: RB on March 29, 2019, 07:15:43 AM
Quote from: Speeddog on March 28, 2019, 07:43:46 PM
...snip

We will have trouble defining what "a little" is.

"a little".... like, this much '||' i think that is pretty close....hahaha
Title: Re: Shim behind countershaft sprocket
Post by: Speeddog on March 29, 2019, 08:23:58 AM
Quote from: RB on March 29, 2019, 07:15:43 AM
"a little".... like, this much '||' i think that is pretty close....hahaha

That's a good start!

I'd say that's an allowable amount of float.
Title: Re: Shim behind countershaft sprocket
Post by: Howie on March 29, 2019, 09:31:48 AM
Is your sprocket held on by a big nut or a retaining plate secured with small bolts?  Yes, float is normal, no spec I know of.  The retaining plates do wear though.
Title: Re: Shim behind countershaft sprocket
Post by: dusty on March 29, 2019, 12:44:39 PM
Quote from: Speeddog on March 29, 2019, 08:23:58 AM
That's a good start!

I'd say that's an allowable amount of float.

It wobbles a little more than a bit, but not as much as a lot ;)

Kidding, I'll get a quick video of it later when I put the chain back on.

Quote from: howie on March 29, 2019, 09:31:48 AM
Is your sprocket held on by a big nut or a retaining plate secured with small bolts?  Yes, float is normal, no spec I know of.  The retaining plates do wear though.

It's the old sort with the retaining plate and two bolts, with a brand spankin new plate from Italy. Or, wherever it came from off ebay.
Title: Re: Shim behind countershaft sprocket
Post by: koko64 on March 29, 2019, 03:27:07 PM
Floating sprocket.  [thumbsup] Good practice using a fresh plate with each sprocket change.