Revalving the KYB

[Anders]

After some hours riding with the KYB forks, I feel some need for reducing the compression damping. It has now got std 2008 yz250f valving.
I feel I have 3 alternative routes:
1. The best and most expensive: let the local guru do the work. I am convinced that the result will be good, but he is expensive and have a long lead time.
2. Buy a Gold Valve kit and follow the instructions...
3. Buy a selection of KYB shims and start a trial and error process.

I presume the result of 2 and 3 will depend heavily on how good advices I can get, as my experience with suspension revalves are nil.
I also presyme that the main upside of the gold valve approach would be the fact that Racetech would then supply a "recipe.

Any opinions on this matter?

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[gasgasman]

I would lower the fork fluid height first.
I am using 300cc per leg with excellent results on the stock valving.

I don't know if you can purchase this fork fluid. Amazingly, it works.
http://http://smartperformanceinc.com/215VM2K5.html

 

[Anders]

I did reduce the level to 300cc. It helped, but not enough. I am a slow guy that needs plush suspension

Regarding the smart performance fluid, I presume I could have it shipped to Norway, but the cost would end up pretty high. I tried to contact Smart performance a couple of weeks ago, but did not get any response.

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[Anders]

During my summer vacation I ordered a Gold valve kit and installed it per the included instructions and the valving specs retrieved thru the Racetech Digital Valving Search.

Not too difficult to do. I ended up with a fork a lot closer to what I want, but after using it for a month now, including two races, I think I am ready for the next iteration towards the "perfect setup".

I think the fork is quite OK in the low speed department, but needs more plushness when hitting 15-20cm (6-8 inch) high roots or rocks.

The big question now is what part of the compression circuit do I change?
The Racetech shim stack is divided in four different parts, the low speed, the high speed, the preload (set to zero in my case) and the restrictor size (to reduce the port size in the piston).

I guess reducing the high speed stack or increasing the restrictor openings should bring me in the correct direction.

I'll post some updates as the process continues...

 

[Jakobi]

I'd personally start with the simple things as suggested. Oil viscosities and volumes, spring rates and preloads, and then if you still can't find a good balance a revalve. Whether you research some shim stacks, or employ a reputable tuner to do the work is another thing. You could also look at purchasing a stack and/or shims from a tuner and physically doing the work yourself.

 

[Anders]

You could also look at purchasing a stack and/or shims from a tuner and physically doing the work yourself.

That's in a way what I did by purchasing the Racetech Gold Valve kit. And I am quite (but not completely) happy with the result. But Racetech has a friendly service departement, and they usually answer my questions within 24 hours. I sent them a email now, and hope to get a response before I get out of bed tomorrow morning.
Of course, a big part of the whole thing is to learn something new (this time it's suspension setup).

 

[Jakobi]

That's in a way what I did by purchasing the Racetech Gold Valve kit. And I am quite (but not completely) happy with the result. But Racetech has a friendly service departement, and they usually answer my questions within 24 hours. I sent them a email now, and hope to get a response before I get out of bed tomorrow morning.
Of course, a big part of the whole thing is to learn something new (this time it's suspension setup).

Indeed you did..

I was simply suggesting the parts may be cheaper to work with the standard valves and buy shims and maybe some coin to the tuner for a 'better stack'. Shims are cheap, gold valves not so much, and they also only really offer a generic stack which while it may be an improvement initially can still be greatly improved on. I guess this is where you are though.

I personally just spent even more money and went for the Ohlins, which eventually puts you back in the same place where you find things you want to change anyway Not so much with the forks in my experience, but definitely with the shock.

 

[zeuszuki]

After some hours riding with the KYB forks, I feel some need for reducing the compression damping. It has now got std 2008 yz250f valving.
I feel I have 3 alternative routes:
1. The best and most expensive: let the local guru do the work. I am convinced that the result will be good, but he is expensive and have a long lead time.
2. Buy a Gold Valve kit and follow the instructions...
3. Buy a selection of KYB shims and start a trial and error process.

I presume the result of 2 and 3 will depend heavily on how good advices I can get, as my experience with suspension revalves are nil.
I also presyme that the main upside of the gold valve approach would be the fact that Racetech would then supply a "recipe.

Any opinions on this matter?

Sent from my OMNIA7 using Board Express

Are you using "S1" in the damper cartridge ? This is important for proper damping performance in Kyb SSS forks.

 

[Anders]

Are you using "S1" in the damper cartridge ? This is important for proper damping performance in Kyb SSS forks.

No, I'm not. I use Ohlins high performance front fork fluid no 5.