On the S bike? Umm 22 years ago.
Brain has no recollection unfortunately.
Let me check notes…
Ah!
The clutch bleed nipple for a BMW R1100S is on the end of a hose behind the main frame member, in front of the rear wheel on the left side. The hose is hard to see, but you can feel for it by reaching your fingers around the frame below the body work and above the left foot peg. Pull the hose out in the open to find it.