Here are some numbers I came across when I redid the rear shock on my B4.
Here's something to remember about swapping shocks though. Although anything feels better than a sacked-out rear, you have to realize that unless you know what the leverage ratios, etc are that these shocks were designed for, you stand a chance of not ever getting them dialed in on your bike. This is the argument for a proper aftermarket rear shock built closer to spec for the bike. But, if you're poor like me, you'll take what you can get courtesy of EBay.
For reference sake:
OEM B4 305mm 400lb
01-02 GSXR 1k 329.5mm 430lb
01-03 GSXR600 325.5mm 450lb
GSXR1100 w/ remote reservoir: 315mm 500-470lb depending on year
05 GSXR 1k 325mm 450lb spring
06-07 GSXR 600-750 317mm 526.4lb
You can find these numbers a variety of places but I think I got a good deal of them from RaceTech's site as I scribbled them down on some index cards.
I think that BrianM had indicated that an ideal spring weight for the B4 with an average weight rider, the spring rate should be between 450-475 lbs with an optimal length of 320mm MAX. Any greater than that you'll be hacking alot of material from the cushion lever and also jacking up the rear over 2". Whether or not that's a good thing depends on your idea of stability, but also make sure you run the proper amount of slack in the chain as well. A raise that high, you're looking at motocross levels of slack. It's been done though. You can compensate with the dogbones but then you're really messing with leverage ratios etc.
Any shock that you install lest the B12 ones will require some slight machining to the cushion lever and perhaps to the shock clevis to allow it to fit. The shocks that require the least amount of mods would be:
-B12 pretty much a bolt-in affair
-GSXR1100/750 with remote reservoir
Also, either of these shocks will raise the rear about an inch to 1.5".
Anything with the reservoir attached will require modification to move either the battery box or coolant reservoir out of the way.
Here's my personal experience:
I weigh in at 175 in leathers and 155 without. With the GSXR1100 rear shock, I had to run the preload in kind of far to set the rear sag at 25mm (my preferred setting). This resulted in no static sag but the settings were able to be controlled by the shock's damping. I had to lightly sand the cushion lever as well as the clevis in order for this to fit. You also have to lightly shape the upper eye to fit into the stock mounting bracket.
When I went to the newer GSXR 600 rear shock, the higher spring rate allowed less preload and also a static sag of around 10mm while allowing my preferred 25mm of rider sag. It has high speed comp as well as low speed comp although I had to run the rebound in fairly high. It's nice to be able to set high and low speed as you can dial in your bump absorption as well as set up squat when you're on the gas.
On track, you also figure out why serious riders swap these out for Ohlins, Penske etc. I was able to get the fluid to really thin out midway through the first session and endt up having to dial in more of everything to compensate. If I get really bored, I'll just take it apart and rebuild it with better fluid and perhaps find a way to add more rebound damping to the shock. That's a whole nother ball of wax.
Installing the shock required me to use a different container for the coolant overflow to allow the remote somewhere to go. There have been people that drilled bracketry to move the whole battery box/coolant res back and up (herr tod I think) but I felt it was just as easy to use something else. This shock raised the rear something like 1.75" and I had to fabricate something for the center stand stop as it was now useless (yes I still have the center stand).
So to sum up this ridiculous dissertation:
-Any shock is better than the sacked out B4 but will be a compromise
-Any shock longer will raise the rear
-Raising the rear will quicken the bike and increase clearance
-You will have to adjust chain slack accordingly not to bind the suspension
-You can go longer but will require more setup/modification
-You will have to modify unless it's the OEM B12
-Track use, it'll work but not as well as aftermarket
-Your front end will totally need a rehab to match the rear
Good luck!
-Randy
Topic: oh by the way here is a shock if anyone wants it (Read 5359 times)