Replacing large left seal in rear drive, '81 R100

[Duane Ausherman]

You must remove the cover and gear to get to the seal. Otherwise you would ruin the edge that keeps it in place.

[ME 109]

You must remove the cover and gear to get to the seal. Otherwise you would ruin the edge that keeps it in place.

This is for a modern 1981 bike, Duane. The seal can be replaced without removing the cover.
Or, are you referring to the small seal on the driveshaft side of the fd?

[Duane Ausherman]

ME, Oops, I hadn't paid attention to the year/model. Basically, on a later bike I don't know squat, so I generally stay out of it.

[mattcfish]

Modern cardan gaskets are thicker now than the original paper thin ones. Replacing it will most likely require re-shimming.

How much thicker are the cardan gaskets vs. paper at the proper torque?
The shims only come in .05mm increments from 1.5mm up to 2.5mm on the Max BMW site.
It may be thicker out of the box, but If the cardan gasket is less than .05mm thicker at torque then it's a non-issue.

[montmil]

Modern cardan gaskets are thicker now than the original paper thin ones. Replacing it will most likely require re-shimming.

How much thicker are the cardan gaskets vs. paper at the proper torque?
The shims only come in .05mm increments from 1.5mm up to 2.5mm on the Max BMW site.
It may be thicker out of the box, but If the cardan gasket is less than .05mm thicker at torque then it's a non-issue.

Good point and I was waiting for this answer. I've replaced several Cardan cover paper gaskets and just supposed I was as lucky as that blind hog who finally found an acorn.