OK, kept digging into the bike and found the transmission input and output splines to both be in great condition. :2thumbup:
Was having some clutch slipping last fall so I was going to see what the clutch looks like. Was worried the O-Ring went out and got the disc wet or something. Not so.
Having never worked on a BMW style single disc clutch before, I still feel this clutch friction disc is in sad shape. Measuring the thickness in various places, it went from 0.174 to -.185 inches (don't have a metric micrometer). Manual says anything under 0.177 needs replaced. Therefore, it's gone.
Interestingly, the rear cover has rust all over the outside. Coupled with that, the friction disc surface looks strange. Almost like there was water in the clutch area (perhaps condensation). Any input?
The O-Ring looks in good shape but I will be replacing it anyway since I am already in there and it is likely 27 years old.
Got to say, clutches on Japanese machines are a whole lot easier to deal with.
The clutch disc:

Close up of clutch disc:

Transmission input splines:

K75 feelings particularly naked:
