Found something on my garage floor after I rebuilt clutch and oil seal/o ring on my 1996 K1100LT.  I fear it might be the stop disk, item #10 on clutch fiche.
Clutch seems to work well and I have put about 400 miles on the bike with new clutch.  From what I can tell the k75 does not have this part but k100 and K1100 have this stop disk.
what does it do and what ID/OD is it?  cant find dimensions of the stop ring on vendor sites.  I need to know if this needs to go back into my clutch if it is indeed the stop disk.  Not looking forward to taking the clutch out again but time will tell.
thanks,
Jerome in Portland

edit:  washer I found is 37 mm OD, 28 mm ID, and 1.6mm thick.  hopefully this is not the stop disk.  It is also steel and attracted to a magnet.  Would this confirm that it is not one of my clutch project parts?  The thickness alone tells me it is probably not the stop disk, fingers crossed.

I can't answer all your questions but they can be purchased from here Tills - Clutch This might be able to give you an idea if it is the part you found.

Your right, the k75 doesn't have it, as it has balance weights instead of an absorber.

It acts as a thrust washer. I have one for a k100, it's non metallic (fibrous and brittle, almost looks plastic) Measures about 36mm ID, 50mm OD.  I think you should have it, do you hear a bit of rattle at different revs with the clutch pulled in? At different stabilized rev ranges? Or rolling off the revs, or something else? It helps to eliminate end float and minimise wear, amongst other things. There's a bit of a description in the thread "how to understand the k100 engine output shaft" on page one of the "how to" chapter in the technical section. 

I'll guess it stuck to the back of the clutch housing when you removed it, and fell off along the way. You want to replace it with one of the same thickness. 

Your second go at it will be quicker and easier, so not that bad.

At $47.74, you better be very careful not to break or lose that ring!

Point-Seven-five wrote:At $47.74, you better be very careful not to break or lose that ring!

And. . . . it needs to go back in.

attitude wrote:

edit:  washer I found is 37 mm OD, 28 mm ID, and 1.6mm thick.  hopefully this is not the stop disk.  It is also steel and attracted to a magnet.  Would this confirm that it is not one of my clutch project parts?  The thickness alone tells me it is probably not the stop disk, fingers crossed.

It's not the stop disc. I can't think of a washer that size for a clutch job. Does it look like a fit for some other job you've recently done? With the ID and OD so close, it's enough to make you wonder if it's a shim. 

To explain an earlier point a bit better, the stop disk acts as a thrust washer for the absorber shaft, the K75 doesn't have an absorber, so the stop disc isn't then required.

 The take home message for me about this thread is what a brilliant trick that would be to drop a stop disc on the garage floor of someone who's just done a clutch job.