Dogbones

[tomacGTi]

http://www.burkhartcycle.com/Site/extras/linktable.htm

This guy has aluminum dogbones that you can use for the B4. Remember that stock length is 198.5mm and that 10mm shorter will raise the tail by 40mm.

When I spooned on some Pilot Powers recently, I noticed that the bike was riding a bit higher in the front. I placed the Avon I had just taken off next to the bike and lo and behold the rear Avon is physically taller by an inch as well a smidge wider. I already had the front end of the bike dropped through the triples 10mm and did not want to go down anymore. Incidentally, the front Avon is smaller than the PP as well so the whole bike was raked opposite of what it was originally.

Obviously my suspension was set up for the Avons and rode like crap with the Powers, the front end felt really high and turn in was slow. Coupled with the profile of the powers it felt like the bike was going to topple over mid-corner.

I had made a couple of sets of dogbones from some steel stock and the last set was 5mm smaller than stock (193). I also fabbed up some 10mm shorter ones as well. The center stand is pretty much useless on the 10mm shorter bones as they kicked the back up 40mm plus whatever the GSXR rear shock would have raised the rear (another 20mm). All total, 60mm of rise in the back. With the forks set level, the bike was tipping in incredibly but high speed turns were a bit scary. Lots of clearance though, besides being ridiculously kicked up in the back, it rode quite well.

The 5mm shorter than stock puts the rear tire on the ground when the center stand is down so once again, pretty much useless. That and I had to make a spacer for the stop so it wouldn't ride up against the chain. It started to rain here when I finally got it all back together so no ride report.

All total, I had spent $40 on steel and drill bits in order to figure out the length I needed to restore the previous configuration of the bike. $22 is all it takes for some CNC'd ones from this guy. I've pretty much deduced that 3mm of change (which is impossible to do with a hand drill) should put me back into the ballpark of where I like the bike to be set up.

If you decide that you'd like to waste an entire day as I did making your own, you're going to need:

-1" x 3/16" steel flat stock
-7/16 drill (you'll still have to reem with the bit slightly to achieve a loose 12mm)

For reference sake:

10mm shorter= 40mm raise
 5mm shorter= 20mm raise
2.5mm shorter= 10mm raise

Stock: 198.5mm

-Randy

[Banditmax]

Or you could buy four spherical rod ends and some threaded bar and a big adjuster nut and have variable height rear end.

[tomacGTi]

I can go to a Home Depot here and get steel versus paying bigger bucks for spherical stuff.

I had looked into parts to make a spherical shift linkage for my VW and it wasn't cheap. The spherical adjustable dogbones that I've seen run in the hundreds of dollars. That and once you get them large enough to handle suspension duties you really start to run out of room back there.

[Banditmax]

yeah i was just suggesting an idea for any guys who were wanting to play about a bit. And you are looking at about £20 per rod end x4 so it'd add up i spose.

[tomacGTi]

That's 80 quid (160 USD) not to mention the special turnbuckle rod with reverse thread on the side.

All total I have $40 invested so far including drill bits and steel. The 6061 T6 dogbone is shipped $22 to the door. For the less than the price of the ends, I've got 3 different lengths to futz with. Granted, it would be a hell of alot easier to just loosen a couple of locknuts and twist away but I'm not made of money and once it's set for the tires, I'm not mucking with it.

Incidentally, with a 40mm raise, the back end hits the ideal 13* angle for squat and compliance according to Traxxion Dynamics. You can get this with a 315mm shock length and 193mm bones.

-Randy

[Red01]

Or you could buy four spherical rod ends and some threaded bar and a big adjuster nut and have variable height rear end.

After my experience with the short life of Heim joints in the suspension of my Jeep, I'd be a little reluctant to use them on my bike.  The ones I had were quality pieces (ie aircraft/mil-spec quality) and only lasted a little over a year doing on & off-road use.  They didn't hold up to the grime well and got sloppy.

It also seems like a heavy alternative compared to flatstock. 
The adjustability might be nice though... at least until you found the length you wanted to stick with.