In
need of more waterproof storage space - as well as a backrest for my passenger,
I attacked the problem of adapting the BMW F650 topcase to the K12. The
problem was how to mate the case with the 'clip-on' topcase base designed for
the K12. I preferred to tackle this challenge to installing the less
appealing Givi case.
Tools used: drill, 1/4" and 1/2" bit, riveting tool, 1/8" and 3/16" rivets.
Supplies needed: F650 case, K1200RS soft topcase bracket, lockset for K12 topcase bracket, K12 topcase base, seven 25mm hex-head screws (of the same size as the stock hex-head screws you will remove from the K12 topcase base).
Place a large towel on your workspace so the case won't get scratched. Open the case and remove the pop-out case floor; set it aside. Turn the case upside down and drill out all the rivets (their faces only) from the outside using the 1/2" bit. Use a 1/4" bit to drill out the faces of the ones holding the locking mechanism. Remove the base and set it aside. Open the case and make sure you have removed all the rivet debris.
With your riveting tool, re-install 
the
metal plate that is inside the case, and especially the four clips on the corner
which are used to secure the removable case floor (circled in red). Also,
put in a couple of rivets to further secure the base, and also some to plug the
holes left when you removed the F650 base's lock mechanism (circled in
yellow). I put rectangles of salvaged black ABS on both sides of the
original lock location and painted the rivet heads black on the outside to make
the repair less obvious.
Take the stock K12 topcase base and unscrew all the hex-head screws. This will separate the black plastic topcase base from the mechanism that secures everything to the platform. Clip the mechanism onto the base and rest the F650 topcase on it, moving the case until it sits on the bike the way you want it to. Mark it's location with tape or a marker.
With the case upside down on the towel, place t
he
locking mechanism in the desired position and mark where you will need to drill
holes for the screws that will secure the locking mechanism to the case.
Before you proceed to the next step, you must make sure that the forward-most
holes will go through the metal plate inside the case (see
detail). Drill the required holes using a 1/4" drill bit.
Secure the base using the seven 25mm screws listed in the "supplies
needed" above. The setup should look like this.
