I'm feeling the back end lower significantly on me when I accelerate, would that be to much rebound?

Thanks.

sam

Nope. Too soft of spring, not enough preload, and no low speed compression damping. Set the sag and see if it close. 28-30mm rider, 5-8mm free. You can't do anything about the low speed compression damping unless you buy an upper end shock, but you can change spring rates which is most likely the problem. What's your weight?

Hmm? I'm 6'3 at 230 pounds.

What I dont understand is all of a sudden it just started. Is there a specific tool used to adjust preload? If not what's the easiest method?

Greatly appreciate the help Philbie.

What bike do you have? It doesn't really matter I guess. You need a different spring. GSXR's are sprung for riders in the 160-180lbs range. Adding preload isn't going to help. Kinda like putting a bandaid on gunshot wound. www.racetech.com (http://www.racetech.com) can give you a pretty good idea what spring you should have in the bike.

Well I went ahead and made some adjustments to rebound/compression. A definite improvement when going 2.5 turns out for both.

I'm not sure what to think. I've had this bike, 04 gsx-r 750, for about a month now and up until about a week ago, I had no problem.

Guess I'll try and adjust preload, if none of that makes a differnece I'll look into purchasing another spring.

What method when adjusting preload will cause the least amount of damage?

Look, listen to Philbie...he's saying you need a stiffer spring, and he's right! Preload will not help your situation. You are experiencing "squat", and the stock spring is way too light for your weight. In addition to a new spring, you may need the shock to be re-valved for your weight/riding style, but it isn't necessary. Or, spend some $ and get an Ohlins/Fox/Penske shock with the correct rate spring for you. If you really want to correct this problem, that is the way to do it.

To set the sag on the rear end, you will use the preload adjuster rings, but these are really only useful if you have the correct rate spring in there to begin with.

When you do that, you can take a long, blunt-ended object (drift, punch, square end of a metal file, etc), and a hammer, and knock the locking ring loose, then turn down/up the spring seat ring, until your sag is set properly, then turn the locking ring back down to the spring seat ring.

thanks guys. i'll look into a new spring. just wish i could afford to replace the whole back end suspension.

any specific type of spring i should look into or will the race tech do?

sam

Go to www.racetech.com (http://www.racetech.com) or the traxxion website. You can type in your weight and type of riding and it will recommend what to use. You can revalve the rear shock which is cheaper than buying an aftermarket shock.

What I would do (because I did do it) would be to keep checking Ebay for a Penske or Ohlins rear shock. I bought a Penske for my 04 for nearly half what a new one costs. You may have to respring but that's only about $100 extra. Worth lookining into. Alot of racers will be selling parts in the next few months.

You won't be able to set the SAG with the stock spring, you weigh to much...same goes for the fork springs...

Might as well do it right, and be done with it...in the end, you'll like the results.. http://www.gixxer.com/forums/images/graemlins/grin.gif

I looked up your recommended spring rates for your weight.

Front springs should be .913 for street riding and .978 for racing. I'd go with .95's in both or .925 (a .90 and a .95 combo). Stock is .85. That's a pretty big difference. I'm about 190lb and put in .925's in mine.

The rear is 7.3kg/mm stock. For your weight it recommends 7.88 for street and 8.27 for racing. I think a 7.8 is available but 8.0 would be pretty good.

With a penske your looking at something in the 475lb/in range. I'm using a 450 and sag is really good.

Just for a comparo, I'm 170 lbs...on my 600, I had .90's in the front, and a 425 lb. spring in the rear...

I'd snag the .95's too...for the forks...

Go find your own topic to help on. This one is mine Greg. http://www.gixxer.com/forums/images/graemlins/flipa.gif

I said stay away Greg. http://www.gixxer.com/forums/images/graemlins/lick.gif http://www.gixxer.com/forums/images/graemlins/lick.gif http://www.gixxer.com/forums/images/graemlins/lick.gif

Philbie said:
Go find your own topic to help on. This one is mine Greg. http://www.gixxer.com/forums/images/graemlins/flipa.gif



Oh..sorry, Mr. Suspension Guru...
http://www.gixxer.com/uploads/hail.gif

http://www.gixxer.com/uploads/bolt.gif

http://www.gixxer.com/forums/images/graemlins/flipa.gif http://www.gixxer.com/forums/images/graemlins/banana.gif http://www.gixxer.com/forums/images/graemlins/laugh.gif

Hey, where did you get the new Graemlins?

Philbie said:
Hey, where did you get the new Graemlins?




Haha...my secret.. http://www.gixxer.com/forums/images/graemlins/crazy.gif http://www.gixxer.com/forums/images/graemlins/grin.gif http://www.gixxer.com/forums/images/graemlins/flipa.gif

Damn you! http://www.gixxer.com/forums/images/graemlins/bitchslap.gif

Philbie said:
Damn you! http://www.gixxer.com/forums/images/graemlins/bitchslap.gif



Geez, right click and save those....I do have more though....just in case.. http://www.gixxer.com/forums/images/graemlins/crazy.gif http://www.gixxer.com/forums/images/graemlins/laugh.gif

to the OP, sorry for the highjacking... http://www.gixxer.com/forums/images/graemlins/grin.gif

haha dorks!

thanks, i'm gonna go with your suggestions

.95's for the forks and an 8 for the rear

Another Gixxer rider SAVED! Good advice folks, keep it coming. I hate to see guys being mislead by others when it comes to suspension. My favorite is "crank down the preload for racing, then un-crank it for street riding...you'll love it!"

That gets me goin' every time!

I hear ya on the preload comment. Then you have to make a rebound adjustment to compensate the added preload. Compression isn't effected very much and normally not worth messing with in that case.

Spring rates are critical for proper set-up. Sag numbers are relative numbers that really help determine if the spring is close. Oil heights are very important to allow full use of the travel without bottoming.

Oh and Greg, http://www.gixxer.com/uploads/gayfight20.gif.

Philbie said:
I hear ya on the preload comment. Then you have to make a rebound adjustment to compensate the added preload. Compression isn't effected very much and normally not worth messing with in that case.

Spring rates are critical for proper set-up. Sag numbers are relative numbers that really help determine if the spring is close. Oil heights are very important to allow full use of the travel without bottoming.

Oh and Greg, http://www.gixxer.com/uploads/gayfight20.gif.



Ya just had to add those...didn't ya..? http://www.gixxer.com/forums/images/graemlins/laugh.gif
here's one for you... http://www.gixxer.com/forums/images/graemlins/flipa.gif http://www.gixxer.com/forums/images/graemlins/grin.gif
http://www.gixxer.com/uploads/YourBoogieMan0.jpg

http://www.gixxer.com/uploads/doublefinger.gif

Quick question? Is there a big difference in springs by brand?

I was checking out LE Race Suspesion and they sell Eibach. I was going to pick up the 450lbs/8.0 spring but I'm unsure of the length?

I checked the Eibach website but they dont list an application for an 04 gixxer 750.

sam

Hyper Coil and Eibach make very high quality springs. I have the proper rates for the GXR's in stock in Hyper Coil. You need a 2.25 x 7 inch spring in a 425 or 450 lb/in depending on your eight. With your GIXXER.COM discount the spring would be $80 plus shipping.

Pete, I think he's 230lbs. I figured he'd be pretty close to the 475 rate. I'm 190 with a 450 on a Penske triple, but I'm on the bubble for spring rates.

I'd start with the #450, I weigh 230 and that's what I use, even at NHIS where we typically use stiffer rear springs than other tracks. I can always swap with him, and remember there is no such thing as the right spring for a given rider weight, you need to test several rates and it will change from track to track. I carry #400 -#500 for the GSRX's in the trailer just for that reason.

Thanks Pete http://www.gixxer.com/forums/images/graemlins/thumb.gif.