GSXR rear shock upgrade

[psych0hans]

For all the guys using GSX-R600 shocks on your bikes, here's a way you can upgrade your shocks for not "too much" money.

Copied from GSXR.com

Originally Posted by SuspensionGooRu

In my spare time when I am not working on Pratt Whitney F100-220 jet engines I am playing around with motorcycle suspension that I learned how to do from a very good friend.

A lot of riders always ask me what they can do to upgrade their suspension. When I throw some numbers out there they step back a little, because they have usually spent all their money on looks and sound. So a lot of riders will put some money into their front forks, but have a problem with dropping large ammounts on an Ohlins or Penske rear shock.

So I found a great way to upgrade the rear shock on most 2001 through 2006 GSXR and SV model bikes and wanted to share it with you and it will not empty your piggy bank.

The stock shock that comes on the 04/05 GSXR 600/750 model is a Showa brand shock and has an awesome feature about it. The Compression adjuster has a tapered needle and shim stack instead of a high speed pop off valve that comes on most KYB stock rear shocks. The picture below is both shocks side by side.

[IMG][/IMG]

Here is a picture of the compression adjusters side by side. The Showa with the tapered needle and shim stack is on the right and the KYB with the high speed pop off valve is on the left. That is the main difference in these to OEM stock rear shocks.

[IMG][/IMG]

So what I do to the Showa to upgrade it is take it completely apart and clean it in a solvent tank.

[IMG][/IMG]
[IMG][/IMG]
[IMG][/IMG]
[IMG][/IMG]
[IMG][/IMG]
So after the shock is disassembled and cleaned you then have to grind the shaft nut down because it is pined from the factory and if you try to remove it without doing this your will ruin the threads.
[IMG][/IMG]

Then after the shock is completely disassembled and cleaned, I then replace the factory .15 shims with .20 and .25 shims to give it an incredibly increased amounts dampening. I then replace the factory piston with an after market high flow piston that weighs 1/3 less then the OEM piston. By doing this you decrease the friction and have less mass weight and a smoother operation rear shock. Finally I recycle the worthless factory progressive spring and replace it with a straight rate high quality aftermarket spring. By doing all of this you get a high quality rear shock with a larger adjustability range on both the compression and rebound side. Not to mention you can select what size spring you need for the model of bike and weight of rider so that you can dial in your sag correctly and still have free sag.

Oh and for the drag racers who are on a budget all you have to do is add a couple of 38mm shims on both the compression and rebound side and go up a couple sizes on the spring to make this shock perfect for launching your bike down the straight away.

This is what it looks like when it is all done.

[IMG][/IMG]

Wants some more ride height just add a few spacers to the top of the clevis.
[IMG][/IMG]

This 04/05 GSXR 600/750 rear shock is a great up grade to your 01-06 bike even if you do not have the means to rebuild it. You can just throw a 450 to 550lb aftermarket Eibach spring on it, and it will improve your rear suspension.

I'm just curious if this will work with the '06 shock we currently use.

[Somchai]

Originally Posted by psych0hans

For all the guys using GSX-R600 shocks on your bikes, here's a way you can upgrade your shocks for not "too much" money.

Copied from GSXR.com



I'm just curious if this will work with the '06 shock we currently use.

Good find and information, bro. I think this is useful for many shocks.

[Rexbo]

thats badass! I've found that by swapping the softer spring onto the shock, as well as dropping it onto a lighter bike, the damping is pretty darn good. However, the lighter piston and the finer adjustability can never hurt!

[psych0hans]

Originally Posted by Rexbo

thats badass! I've found that by swapping the softer spring onto the shock, as well as dropping it onto a lighter bike, the damping is pretty darn good. However, the lighter piston and the finer adjustability can never hurt!

Yeah, but the amount of money you need to spend on all that... That could definitely hurt... Lol... Still planning on getting it done tho... Eventually...

[psych0hans]

My new 8.0kg/mm spring.

[choneofakind]

Is there a calculator somewhere online for calculating rear spring rates?

[psych0hans]

Originally Posted by choneofakind

Is there a calculator somewhere online for calculating rear spring rates?

The race tech site has one.

[choneofakind]

Link? I've used the one for fork springs, but I have no idea about one for rear springs.

[psych0hans]

Originally Posted by choneofakind

Link? I've used the one for fork springs, but I have no idea about one for rear springs.

http://racetech.com/VehicleSearch you'll have to call/mail them for your bike, since they don't actually make them for our bikes... I'm using a gsxr shock so I mailed them with my details and they came up with 8.0 kg/mm for me.

[BRad704]

I've heard that the online Racetech calculator is not quite accurate. Would probably be a good starting point, but certainly double-check before ordering anything.

[Rexbo]

Originally Posted by psych0hans

http://racetech.com/VehicleSearch I'm using a gsxr shock so I mailed them with my details and they came up with 8.0 kg/mm for me.

That's what I've got and it works great!

[BRad704]

No personal affiliation with this guy, but I've talked to him on a VFR forum and he comes very very highly respected for fork/shock rebuilds and re-valves as well as being an awesome guru on all thing suspension related.

Once I get the money, I'll probably end up having him do all the upgrades on my VFR.

I emailed him before I posted this to make sure he was cool with other random bikes and his comment was "Sure, I can help you out with that! I detail on my site the more popular items, but there is a lot more stuff that I do. Doing custom swaps and setups like you mention are the projects I enjoy the most. "
http://www.daughertymotorsports.com/

[sharky nrk]

Great thread

[red26]

Hi hans, did Racetech made the spring for you or you have them locally made?
I have a company local to me that can make springs for much less cost, but i have to give the dimensions to them (spring total heigth, outlet diameter, coil thickness and number of coils) so if you can provide me with these info it would be awesome!

[psych0hans]

Originally Posted by red26

Hi hans, did Racetech made the spring for you or you have them locally made?
I have a company local to me that can make springs for much less cost, but i have to give the dimensions to them (spring total heigth, outlet diameter, coil thickness and number of coils) so if you can provide me with these info it would be awesome!

Hi buddy, I actually had a GSXR600 shock to begin with, so I just gave my spring supplier that as a sample. The only thing he changed was the wire thickness from 10mm to 8mm and that made all the difference for me. Brought the spring rate down from 9.3 i believe to about 8.0. No, It wasn't made by race tech, they didn't have the rate I wanted and I was getting this for free anyways... Good luck!

[red26]

Originally Posted by psych0hans

Hi buddy, I actually had a GSXR600 shock to begin with, so I just gave my spring supplier that as a sample. The only thing he changed was the wire thickness from 10mm to 8mm and that made all the difference for me. Brought the spring rate down from 9.3 i believe to about 8.0. No, It wasn't made by race tech, they didn't have the rate I wanted and I was getting this for free anyways... Good luck!

Cheers!

[red26]

I have ordered a sping (based on my weight 70kg as per Race tech). SHould be about 8.22kg/mm
I have a spring maker here that charge me around $30 for a custom made spring

Raw material : Steel
Wire Diameter : 10mm
Outer Diameter : OD 83mm top
OD 86.5mm Bottom
Inner Diameter : ID 60.2mm top
ID 64.3mm bottom
Length : 196.5mm
Number of Coil : 6

will update here on how it feel

[red26]

The spring works great. I did get a better laptime on that (that’s all that matters), apart from the ignition advance + Skorpion full system. The spring is softer, so after adjusting the sag I found the riding was lowered. If anoyone is thinking the same thing, consider longer spring or new dogbone to compensate.