After replacing the front springs with Sonic units I wanted to get the back end up to speed as well.  I first installed a shock off of an '03 Katana 750, or at least that's what the ad said it was.  I might as well have replaced the stock shock with a 2x4  .  I'm 200 lbs and there was no sag even with the spring collar spun all the way out.  The next obvious option was an R6 shock so I got lucky and picked one up off of an '08 for $35 including shipping. 

The only mod that I found necessary was to fabricate two small sleeves for the bottom of the R6 shock mount.  I found a steel sleeve for $1.50 at Ace Hardware that was just a tad too big to fit into the mounting hole of the R6 shock as well as a smidge to small to allow the mounting bolt to pass through. I found a drill bit that was slightly larger than the inside diameter of the new sleeve and drilled it out.  I'm guessing it took out about 1/32".  Then I placed the drilled out sleeve in the vice and using my trusty Dremel tool and a grinding stone I ground away material from the outside of the sleeve.  Then, using a cutoff wheel I cut off .25" for installation into the R6 shock.  I hammered them in and ground out the inside just a little more and the bolt fit perfectly  .  Unfortunately, the stock bolt on the lower mount for the shock is too small to use with the R6 shock.  Fortunately I had one that would work laying around.

Here's whats left of the sleeve
     

Installed in the shock


After that the installation was a breeze .

The test ride made all of the effort worth while.  The R6 shock provides a firmer yet compliant ride and I haven't even tried dialing in the various settings yet. 



Katana / R6 / GS

Nice work and great info and pics    Any idea what year R6 the shock came off of?  I think when we put Kay's on we were able to swap parts off the R6 shock pivot (or maybe off the GS's?) to make the bottom fit correctly.

-Jessie

Mine came off of a 2008.  The bottom shock bolt from the GS will work but I wasn't really comfortable with the limited amount of threads that were showing once the nut was installed.  That said, if I were to use the stock bolt I would definitely apply some thread locker.

FYI: The spacer that comes from the R6 will slip right into the stock GS500 linkage. Everything will bolt up as if it was designed to fit together. Much easier, cheaper, and less error prone than fabricating your own spacer.

QuoteFYI: The spacer that comes from the R6 will slip right into the stock GS500 linkage. Everything will bolt up as if it was designed to fit together. Much easier, cheaper, and less error prone than fabricating your own spacer.

That's good to know.  I figured that there was no way the gods of good fortune would allow for it  .  At least I got to play at being Joe Fabricator and custom make some parts  .

You'd be surprised by what fits where (e.g. Yamaha valve shims will fit a lot of Suzuki and Kawasaki bikes)... Especially true given how many parts on a modern bike are bolt on from other manufacturers.