2001 750 - Countershaft/lay shaft. How much trouble am I in?

[EF]

As you can see this is a very worn lay shaft. This makes my sprocket retaining plate wear pretty fast, though I'm not quite sure how fast. So far I've got 1000 km on it, but the wear is quite noticeable. The last one lasted a season.  I am hoping it's just initial wear, and that the retaining plate will stop/slow down the wearing at some point. Long shot, I know.



I know the retaining plate i supposed to last as long as the sprockets and chain, and I'm quite sure my plate doesn't last that long. I would settle for a season, or even half a season, but 1-2000 km is a little short.

So, do I need to change my lay shaft? Is there some other, less costly solution? Or am I worrying too much?
And finally, is this normal for a 10 year old bike?

[Ddan]

It's definitely not normal, I've got 40K on mine and haven't replaced the retaining plate.  I think you have an alignment issue with the chain/sprockets that's causing your problem

[Speeddog]

That wear on the countershaft is not normal... but that fact doesn't help you a bit.

as Dan said, you may have a chain/sprocket alignment issue, it's worth verifying that.

I'm pretty sure the end of your countershaft has a threaded M8 hole, so you could make a retainer plate that bolts to the sprocket with the 2 M5 bolts and to the countershaft with an M8 bolt.

[EF]

My first assumption was, as yours, that the chain and sprocket was not aligned, or hadn't been at some point (maybe even from the previous owner). But as far as I can tell, this is not the issue anymore. I'm using a alignment tool to be sure (the thing you put on the rear sprocket and has a pin that goes down the line of the chain). It's not a laser though   

It may be that the chain has been too tight at some point, since I've raised the back, and no one told me to slacken the chain  .

I reckon that with such a worn countershaft, the retainer plate will wear abnormally anyway, even though the chain/sprocket is aligned. Right?
Or could there be other things that does this? Everytime I look, the sprocket and retainer is "pushing" the worn part of the countershaft. I assume this is because it's worn, and that's the easyest direction for the sprocket to go.

Yes, Speeddog, I've got a threaded M8 hole, and I've seen somewhere, I think on an other forum, someone making a retainer plate like the one you describe. That involved, I  think, welding two or three retainers together, and in the end i didn't seem to work. It was shaken loose all the time, even with locktite. Is this the same as you had in mind?

[Desmo Demon]

I am hoping it's just initial wear, and that the retaining plate will stop/slow down the wearing at some point.

My ST2 is worn similarly, but on the splines closest to the case. I believe mine first occurred when either the retaining plate wasn't hardened correctly or from flipping it during a sprocket cleaning or change, and the extra slack made it wear faster. My output shaft is worn so badly that the new retainers are only lasting 2000-5000 miles.

So, do I need to change my lay shaft? Is there some other, less costly solution? Or am I worrying too much?
And finally, is this normal for a 10 year old bike?

Ideally the cases need to be split and the shaft replaced. I tried a fancy retainer system, but it didn't work. I wound up having an old sprocket cut down to act as a spacer between the case and drive sprocket and then use a new retainer to hold the drive sprocket from walking off the shaft. A snap ring can be used instead of a factory retainer to prevent the sprocket from walking. I learned of this design from a guy on the Ducati.ms forum a few years ago. Sprocket retainer failures are not rare.

I wrote about the old-sprocket-as-a-spacer design in the latest issue of the "Desmo Leanings" for the US Desmo club magazine. I'll see if the e-copy is on the website. Edit - no it is not listed, yet.

http://usdesmo.com/leanings.html

I'm pretty sure the end of your countershaft has a threaded M8 hole, so you could make a retainer plate that bolts to the sprocket with the 2 M5 bolts and to the countershaft with an M8 bolt.

I tried this, but the trick is that the pounding back-n-forth from the freeplay between the shaft and sprocket teeth with jack-hammer the bolts loose. If the threaded hole on the end of the shaft is to be used for a retiainer system, it needs to be able to rock with the sprocket without loosening the bolts. I believe I wrote about my fancy design that failed on the ducati.ms forum and also on the forums.ducatipaso.org forums.

Edit - You'll have to overlook the ridicule for how dirty my bike is, but here is the thread that I started on the ducati.ms forum:

http://www.ducati.ms/forums/11-ducati-motorcycle-chat/58083-counter-sprocket-retainer.html

[Speeddog]

My ST2 is worn similarly, but on the splines closest to the case.

~~~SNIP~~~

Heh. 

Like my friend's '98 ST2:



And it's VIN is in the range specified in the linked article.

I may do your 'cut down sprocket as spacer' method.