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Discussion Starter #1
I'm having a hard time getting my '99 GSXR shock set up properly.


I don't want to hear buy brand X shock, or send it to this place and have this or that done to it. I've read everything I can get my hands on about suspension tuning and am still baffled.



If you have an unmodified GSXR shock on your 1st gen., please post up your year/model shock, weight (not necessary, but helpful), preload, compression, and rebound settings along with your opinion of the shock's performance. Thanks.
 

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What baffles you?
 

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You're looking for a simple single answer to a very complex question with many variables affecting the outcome. It doesn't matter what someone else is using for settings, they're not using your exact shock on your exact bike with your exact riding style. Read this, it's for Ducati's but it will point you in the right direction:
http://www.section8superbike.com/suspensionsetup.php

And don't discount the fact that if you can't get it to feel right, you may have a problem with the shock. It may be low on Nitrogen, old crappy oil in it, etc.
 

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Discussion Starter #5
Nosquid-- Specifically, large bumps like expansion joints jar the piss out of the rear. Almost as if the shock is too stiff, yet I know the spring rate is less than the stock.


jarelj-- Thanks for the link. I'll read it again if it's one I've already read. Yes I had considered that the shock was toast when I scored it off ebay. Yes I understand shock performance is rider and machine/set up specific. Finding out what settings others have had success with will help me troubleshoot my problem and answer both questions...
 

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Six Chin Skinny said:
Nosquid-- Specifically, large bumps like expansion joints jar the piss out of the rear. Almost as if the shock is too stiff, yet I know the spring rate is less than the stock.
That's because of damping. Most likely, too much compression damping. Try softening it a little.
 

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Unfortunately nothing can be done to make it feel right. Get the sag close and soften the compression adjuster as much as you are comfortable with. It is simple - it is valved wrong for your use. Good luck
 

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Discussion Starter #8
Maritan said:
Six Chin Skinny said:
Nosquid-- Specifically, large bumps like expansion joints jar the piss out of the rear. Almost as if the shock is too stiff, yet I know the spring rate is less than the stock.
That's because of damping. Most likely, too much compression damping. Try softening it a little.

I've run many combinations of compression and rebound damping and have been unhappy with all of them to this point. It always seems like the rear is getting bounced around...

How noticeable should the difference between full soft (slow) and full hard (fast) be?
 

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I'm not sure but probably not a huge difference in terms of what you're looking for. It is a low speed compression damping adjuster so I doubt it will do a lot for bumps. Some but not much.
 

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Don't beat yourself up here. Many crap oem shocks have very little adjusment. Meaning you turn the screws not much happens. Or at least not until the last bit of adjustment.

You also know the srad shock has a very soft spring compared to the SV. I had one for a while. I had the spring preload on max and still had 2 inches of sag. I threw it out and bought a Fox.

I will admit despite the shortcomings of the srad shock the bike did handle better than with the original shock.
 

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Do you have the proper sag set up?
 

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The adjusters on the shock are low-speed compression and low-speed rebound adjusters. High-speed compression damping controls the shock's response to sharp bumps (i.e. expansion joints, etc.). This is not externally adjustable, only revalving can change the high-speed compression rates. You can also get the jarring sensation from an incorrect spring, which it sounds like you have.
 

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Discussion Starter #13
NOsquid said:
Do you have the proper sag set up?

Been messing with it this afternoon. My initial results and opinions are based on 2 preload settings: 8 threads showing above collar and 2 threads showing above collar. I'm starting a new round based on 13 threads showing above the collar.

At the most recent lowest preload setting (2 threads) I had free sag of ~14 mm and total sag (me on the bike) of ~40 mm. I understand this is too little preload but am a little disturbed at the damping adjustment's lack of ability to counter-act low (soft) preload.

The shock, now based on higher preload (13 threads), is now almost topped out at rest (~2 mm free sag) with ~16 mm total sag.
 

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Discussion Starter #14
Nosquid and jarelj-- What is the reasoning behind only low speed damping adjustment? Would it not be more useful to adjust high speed damping?
 

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Six Chin Skinny said:
Nosquid and jarelj-- What is the reasoning behind only low speed damping adjustment? Would it not be more useful to adjust high speed damping?
Yes, high-speed compression adjustments are very useful. All you need to do is buy a Penske Triple and you'll have them! :wink: The design is more complicated and therefore more costly, which is why "normal" shocks don't have them.
 

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Discussion Starter #16
jarelj-- The light bulb, once dim, is now warming up inside my dense skull
.


I was under the (apparently) mistaken impression that current supersport factory bikes had both low and high speed damping adjustments. Would it be accurate to say that the damping adjustment capabilites commonly available on OEM shocks are basically worthless farkles?


I'm beginning to understand the importance of both proper spring rate and preload on shock performance, as well as the reasoning behind the astronomical cost of upper tier suspension components...



p.s. Just took a short ride after completing the latest set up. Feels quite a bit better, but it was only a run to the corner store...
 

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They're not quite worthless, it can help to adjust for squat (low speed damping). But people buy the shocks from other bikes and reason that since they're "fully-adjustable" they can make them work perfectly on the SV, which is wishful thinking. Even a Penske triple has to be set up correctly internally ideally, there is no such thing as "fully-adjustable."

I would back off the prelaod, your current setting is extreme, the suspension needs room to extend. Also, is your bike not feeling unstable at all with the rear end jacked so far up? The first setting you had sounds decent to me (2 threads).
 

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six chin skinny- I found this troubleshooting list for suspension tuning. It might help your cause.....

Motorcycle & Sportbike Suspension Adjustment Inofrmation
There are three possible adjustments on the front and rear suspension of a motorcycle: spring preload, compression damping, rebound damping.
Spring preload sets the initial "stiffness" of the spring. Damping keeps the bike from behaving like an old Cadillac - i.e., still bouncing 10 seconds after hitting a bump. Compression damping slows the shock when it is being compressed. Rebound damping slows the shock when it is rebounding. How about that?
Set the preload on each end so that the bike settles 1/3 of its total travel -- look in your owner's manual for total suspension travel. This ("sag") is measured between (a) the wheel suspended off the ground, and (b) you on the bike with all applicable gear, luggage, passenger, etc. If the forks do not have adjustable preload, set it by using a different length spacer at the top of the fork -- longer for more preload, shorter for less. PVC pipe works well.
You can increase the spring *rate* on the forks by cutting off some of the coils and replacing them with an equivalent length of spacer.
Use less sag for smooth roads and fast riding (e.g. CLASS), say 25%.
On shock absorbers: get the sag/preload right before messing with the damping. Start at the shock manufacturer's recommendations. Only change one setting at a time, and don't change damping more than 2 clicks at a time. For compression damping, increase until expansion joints or sharp bumps are jarring, then back off one click. Don't forget that when you increase preload, you have to increase rebound damping (and vice versa for decreasing preload).
Front suspension symptoms, likely causes, & possible
Solutions:
Symptoms: Not using full travel, feels harsh, poor traction in bumpy corners Causes: Overly stiff springing or compression damping
Solutions: Lower air pressure; reduce compression damping; softer coil springs
Symptoms: Bottoms, soft throughout travel Causes: Spring rate too low throughout travel, or too little compression damping
Solutions: More air pressure; increase compression damping; stiffer coil springs
Symptoms: Bottoms, but compliant over small bumps Causes: Spring rate not progressive enough
Solutions: Raise oil level
Symptoms: Harsh over large bumps, but good over small ones Causes: Spring rate too progressive
Solutions: Lower oil level
Symptoms: Excessive sack, feels soft initially but doesn't bottom Causes: Initial spring rate or preload too low; springing too progressive
Solutions: Add air pressure *and* lower oil level; increase spring preload
Symptoms: Harsh over small bumps but uses full travel Causes: Initial spring rate or preload too high, springing not progressive enough, or too much compression damping
Solutions: Raise oil level *and* lower air pressure or install softer springs; reduce compression damping; reduce spring preload
Symptoms: Takes first bump in a series well but harsh over later bumps, poor traction in washboard corners Causes: Too much rebound damping
Solutions: Use thinner fork oil (or decrease rebound damping if adjustable)
Symptoms: Front end springs back too quickly after bumps, poor traction in bumpy corners Causes: Not enough rebound damping
Solutions: Use thicker fork oil (or increase rebound damping if adjustable)
Rear suspension symptoms & causes:
Symptom: Not using full travel, feels harsh, poor traction accelerating out of bumpy corners
Cause: Overly stiff springing or compression damping, possibly too much preload
Symptom: Bottoms, feels soft throughout travel
Cause: Spring rate or compression damping too low
Symptom: Bottoms, feels harsh, sinks far into travel with rider aboard
Cause: Too little preload, perhaps combined with too soft spring
Symptom: Wheel chatters over small bumps during braking or downhills. Doesn't hook up accelerating out of washboard turns
Cause: Too much preload (perhaps because of soft springs) causing suspension to top out; possibly too much compression damping
Symptom: Kicks over large square edge bumps, but not over large rolling bumps
Cause: Too much compression damping.
Symptom: Kicks over rolling bumps and square edge bumps
Cause: Too little rebound damping.
Symptom: Rear end takes first bump in a series but is harsh on later bumps. Poor traction out of bumpy turns or braking on washboard
Cause: Too much rebound damping.
Symptom: Back end extremely springy and shock doesn't respond to adjustments
Cause: Damping is gone because of low nitrogen pressure, tired oil, or damaged internal components
 

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Six Chin Skinny said:
jarelj-- The light bulb, once dim, is now warming up inside my dense skull
.


I was under the (apparently) mistaken impression that current supersport factory bikes had both low and high speed damping adjustments. Would it be accurate to say that the damping adjustment capabilites commonly available on OEM shocks are basically worthless farkles?


I'm beginning to understand the importance of both proper spring rate and preload on shock performance, as well as the reasoning behind the astronomical cost of upper tier suspension components...



p.s. Just took a short ride after completing the latest set up. Feels quite a bit better, but it was only a run to the corner store...
Yeah, it's not as simple as we all wish it could be, there are many variables when it comes to a good suspension setup. I'm not aware of any sportbike that comes with a shock having a high-speed compression adjustment. The stock Ohlins on my 749R only has a low-speed adjuster, and it has about the best stock suspension in the world. That is not true of most OEM shocks. In general OEM shocks are normally built to a price-point and are not going to offer the ultimate functionality that you could ever desire. Take that one step further and remove a marginally-effective shock from the bike it was designed for and put it on a bike with different linkage rates, weight, etc. and it should be no surprise that it works even worse than it did on the bike it came off of.
 

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Discussion Starter #20
algreen-- Thanks for the link. That is a must have bookmark/favorite for any motorcycle owner. Unfortunately, that page cannot answer the questions of a moto doofus like me... :oops:



jarelj and Nosquid-- Yeah, the preload nearly maxed out will probably be a little on the rough side. I'll find out during tomorrow's commute and post work ride; nothing I can't change on the side of the road if I get nervous. I think I finally understand that I may have been bottoming the shock out when the preload was set to minimum.


"Fully adjustable" indeed. I bit on that one hook, line and sinker.


If you haven't guessed by now, I like to (try to) figure things out, even though I'm dense. I appreciate your patience and assistance... 8)
 
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