So I was looking for a luggage rack for the W650 and in doing some research, it seems there's not much out there, which is no big surprise as this bike was not exactly a top seller.
The two principal options that I found are the Five Stars
rack carried by TwistedThrottle (about $220) and the Ventura
system which is primarily intended to mount their line of soft luggage.
The Five Stars rack has an optional hardware kit that fits Givi Monokey cases, one of which I just so happen to have as a top case on my Tiger. I had the Ventura rack and luggage on my ex-Scrambler and it was nice stuff but I prefer lockable waterproof hard bags so I decided to go for the Five Stars.
Strangely enough TwistedThrottle had a rack in stock so I got it a day or two after I ordered it. It seems to be well-made. I got the pre-assembly done, i.e. installing the Givi hardware kit to the rack. The instructions are in German only but it's easy enough to figure out. There are two pins that get installed toward the front of the rack and the wedge-shaped lock thing that gets installed toward the rear (the side with the notch in it faces the front of the bike). They also supply a few rubber bumpers to fill the leftover holes in the rack as well as two plastic end caps that get tapped into the ends of the rack tubes.
Installation to the bike was pretty easy. You have to remove the red side reflectors if you have them installed - they are allen on the outside and there is a 14mm nut on the back side - you can just barely get a wrench in there between the fender.
The front of the rack mounts on the studs for the rear shocks. Undo the 17mm nuts, put the rack on (I had to "stretch" it a bit to get it over the second stud), then put the nuts back on. The second fixing point uses the hardware supplied in the Five Stars kit, a bolt, nut and washer. The bolt and washer go on the outside, the 13mm locknut goes on the backside and then snug it up. That's pretty much all there is to it. The rack looks nice on there and the bike doesn't look as horrible as I thought it would with a top case on it.
The only thing I don't like about the Five Stars rack is it kinda blocks the neat little grab handles but you can work around it.
Here's the rack installed:
Here's a close-up of the mounting:
Here's a crappy iPhone pic of the bike with rack & top case mounted. It may not look great but man it sure makes the bike a lot more practical and useful: