I have a 1991 K100RS I am fixing up. The existing fairing is in pretty rough shape. I have the chance to buy a complete K1100RS fairing to replace the existing one. Has anyone done this swap before? How hard is it and what bits can I use from my fairing etc? For example do the knee side covers from the K100RS fit on the K1100RS upper fairing? Thanks for any help and advice

I had a scout around in realoem to see how compatible those parts are and it seems to be a bit of a mixed bag. The upper fairing and side brackets are the same. The front forked mounting bracket is not but that could be just a design variation. Seeing as the upper fairing is the same I'd guess that it would fit your K100 bracket. If not, then the K1100 bracket should bolt onto the headstock anyway.

The side fairings are different but the lower bracket is the same so I guess the K1100 fairing may bolt on ok. I don't think your K100 side infill panels will fit the K1100 fairing.

I didn't get to check the belly fairing but if you go to realoem.com, enter the last 7 digits of your VIN and navigate to the.... Frame and mounting parts > Motorcycle trim section, windshield  to find the parts. Then by clicking on the part number you'll come to a list of other models that part was used on.

I've not swapped any of these parts myself but my guess its do-able.
Let us know how you go with this.
Good luck

It should bolt right up.

You can even put a K1100RS fairing on a K75:


The only issue I had in doing that was the brackets that attach to the front sides because those are at a different angle due to the "missing" cylinder at the front of the K75 engine.