I have an 87 K100 RS without additional instruments.
I do see that there is a fuse space allocated for the additional instruments on my panel.
I haven't delved into the wiring yet,
Can I assume that the wiring harness is the same on all models and that it is the instruments that are missing.
That so, what does the end of this additional wiring look like?
I'm wanting to put a powerlet adapter on the switch plate.
Cheers, M

have a look at the interactive wiriing diagram in the download section i found this realy helpful when installing mp3 player

Older bikes have a three pin connector, later ones had a 4-pin one (signal for fuel gauge added.