2002 KX250 re-valve for woods

scotth · May 19, 2003

I am trying to make my KX’s suspension plusher for woods riding. Kawasaki does not diagram or explain the fork valve assembly in the shop manual, does anyone know where to get this information?

I have removed the compression-valving unit from the bottom of the forks and examined it. The first thing I noticed, was the bolt on top of the unit is crimped on. Are there any issues with filing the perforations down to get the bolt off?  The second thing I noticed was the KX has about 4 tapered shims and a stack of what looks like 8 identical shims. Compared to a friend’s KTM 300 EXC that has a plush suspension the KX stack is thick. His stack has about 4 tapered shims and a stack of about 2 identical shims. Is it logical to assume that by removing some of the 8 identical shims I could affect the pushiness of the suspension?  I have not been able to find any good information on the web that explains how to re-valve a suspension. From what I can gather, it is part art and lots of experience.  Can any of you suspension wizards point me in the right direction?

Thanks
Scott

jaguar · May 21, 2003

from http://ericgorr.com/techarticles/susweb.html :
"The shims pose a resistance to the oil flow, which provides a damping effect. The damping effect is directly related to the diameter and the thickness of the shim. The shims act as a series of tiny springs, flexing to increase the flow area for the oil. The greater the flow area, the greater the oil flow and less the damping effect. The first shims that the oil encounters are the ones that affect the low-speed damping. These shims are large in diameter and thin in thickness. The oil deflects these shims easily because of their large surface area and the relatively thin steel poses low spring tension. The shim stack or valving is arranged in a taper shape. The large-diameter low-speed shims are positioned closest to the piston and the small-diameter high-speed shims are positioned farthest away from the piston. The low, mid, and high-speed circuit shims are separated by transition shims. Think of the valve stack as gears in a transmission, and the transition shims as shift forks. The more tapered the valve stacks, and the thinner the transition shim, the suspension becomes plusher in it's handling. "

bscottr · May 21, 2003

Scott,
Click here for the answer to your nut removal question. Step 19.

Good Luck! :thumb:

Scott

JTT · May 21, 2003

Scott, consider that when comparing two different bikes, you need to take into consideration the damping rod diameter, the cartridge diameter and the port sizes on the pistons...it's all related and makes comparing directly difficult, but you can get a general "jist" of it.

As for information on valving and effects of valving...you are in the right place! Do a search and read till your eyes are sore. There's more info on here than anywhere I have ever seen.

bscottr · May 21, 2003

Scott,
I have an ’01 KX250 and really had to work hard to get my forks the way I liked them for the woods. I wanted plush, but not overly soft, as I like some feel and feedback in the front end. I tried a lot of different setups before I hit on what I liked. After riding a ’00 KX125 I found I liked the forks a lot AND they were stock! So I pulled apart the valve stack to see how it was designed. Here’s what I found.

From the piston moving towards the nut:

D= Diameter of the shim in millimeters. T= Thickness of shim in millimeters.

D & T (#) of Shims Note:

24 x 10 (3) The only one with multiple shims.
22 x 10
20 x 10
18 x 10
16 x 10
14 x 10
12 x 10
11 x 24 Clamping shim

I was surprised to find this was a single stage stack, yet it was fairly plush. I installed it and set the oil height at 100mm (Mobil 1 ATF). It was so much better than the stock ’01 KX250 setup and I rode with it for a couple of months. But it wasn’t quite what I was looking for, still had too much feedback in the mid-stroke.

The next change came when I installed the Race Tech mid valve conversion to a check plate. Some folks do not support this method and I wasn’t sure I would either. But I went ahead and tried it because you can always reverse the procedure. This really did the trick and smoothed out the mid-stroke harshness over roots, ruts and rocks. Note: I didn’t install a Gold Valve.

I know there are other ways to make the same gains IRT the mid-valve and the valve stack, but this has proven good for me. I’m interested to hear some feedback on this setup from the smart guys. Maybe it will create a discussion on how they’d expect this setup to work (feel) or not work. I’m always up for learning alternate methods and would like to find out more in the way of bladder removal and the gains expected by doing so.

Good Luck,
Scott

Other good reading:

http://www.mx-tech.com/downloads/28125_valve_installation.doc
http://super-cross.com.ar/suspension_faq.html
http://www.4strokes.com/tech/racesag.asp
http://www.shimprogram.com/overview.htm

flynbryan · May 21, 2003

Originally posted by bscottr
I’m always up for learning alternate methods and would like to find out more in the way of bladder removal and the gains expected by doing so.

Scott you don't need to remove your Bladder !! If your that scared just back off of my rear fender alittle. :scream: I won't call you a sissy....just infront of Gomer, and the guys. :laugh: Seriously I would like to hear some other methods as well. Us backyard garage tinkerers need something to do w/our spare time in the winter.

dbrace · May 21, 2003

I would start of with a 2 stage stack that will still prove to be plush yet still have good bottoming resistance. The first thing i would do is remove the washer that sits under the springs. It will make a big difference,cost nothing and is easy to do.

scotth · May 21, 2003

Thanks to all for the feedback. I have a lot better understanding of the subject after all the reading I have done.

bscottr, I removed the bolt holding the valve stack on. The 02 KX250 stack was just like yours except it has 10 of the 24x10 shims. Did your bike have this setup before you modified it?

2002 KX250 Stock valve stack (base valve)

24 x 10 (10) The only one with multiple shims.
22 x 10
20 x 10
18 x 10
16 x 10
14 x 10
12 x 10
11 x 24 Clamping shim

bscottr, did you buy the Gold valve kit or just the mid valve conversion kit? I have wondered about trying the gold value kit. It sounds like it takes the guess work out of re-valving.  Can anyone comment on how well Race-Techs recommended configurations worked out.

bscottr, I will try your setup with the 3 24x10 shims this weekend and let you know how it went. Thanks for giving me a good starting point. :thumb:

-Scotth

James · May 21, 2003

I did the Gold Valves in my forks and they were too soft for me even though I left the mid-valve in. They were fine for the small bumps but bottomed terribly over bigger jumps. This may be fine for trails but I wanted mine setup for Motocross mostly. The kit I got was the type2 (I think) which has you set everything as a two stage stack. I have reinstalled my stock single stage stack with some modifications. I think I'll be sticking with single stage stacks from now on as they work better for MX and I like them on the trails too.

I am trying the Gold Valve in my 2000 shock for the heck of it. Gotta drill the bleed hole and put it back together. I have been real happy with my home modified shock on the 2002.

The Gold Valve kit will may get you where you need to be but you may need to fiddle with it a time or two (or more). I am pretty much sold on modifying the stock stacks and saving a few hundred dollars.

bscottr · May 22, 2003

Originally posted by scotth
Did your bike have this setup before you modified it?

Scott,
I embarrassed to admit that I can’t lay my hands on my original stack records at the moment. But if I remember correctly, it had a two-stage stack. I do know this, even if I never find those records it’s OK, ‘cause I am not going back! ;)

Originally posted by scotth
did you buy the Gold valve kit or just the mid valve conversion kit?

When I started down this road I bought the Gold Valve kit, but I never installed it. After reading a bazillion posts I found that a lot of the smart guys found that success can be had with the stock valves. (Like James for example). It seems that it’s all about flow, larger ports in the valves = stiffer base valve stacks, smaller ports = lighter valving. (Wade on in here guys if I go astray). So I elected to try different setups with the stock valves.

I’d go with the conversion, unless someone offers up some good stack info on the mid-valve. It’s still somewhat of a mystery for me and because it more difficult to repeat the process over and over, I went with the conversion.

Originally posted by scotth
I have wondered about trying the gold value kit. It sounds like it takes the guess work out of re-valving. 

Originally posted by James
The Gold Valve kit may get you where you need to be but you may need to fiddle with it a time or two (or more). I am pretty much sold on modifying the stock stacks and saving a few hundred dollars.

Ditto
Like James said, if you go with the Gold Valve you’ll still be making adjustments to your stacks until you find what you like. You can buy shims and the conversion for the mid-valve (if you elect to go that route) much cheaper and prolly get the same or better results.

Originally posted by scotth
I will try your setup with the 3 24x10 shims this weekend and let you know how it went. Thanks for giving me a good starting point. :thumb:

I’m looking forward to the feedback. I think you’ll find it’s a step in the right direction. I also found that my clickers had a much wider range of noticeable adjustment than that of the stock setup. Maybe I've gotten a little more in tune with my bike as well, but now I can tell when I make one to two click changes. Before it took big changes to notice the difference.

If you want to hook-up with a bunch of spodes on Monday; James, myself and many more will be at TNT. One of our buds (Whyzee) will be coming down from Raleigh Monday morning. Come on down and we’ll do some tuning. :thumb: Click here for info.

Originally posted by James
I am trying the Gold Valve in my 2000 shock for the heck of it. Gotta drill the bleed hole and put it back together. I have been real happy with my home modified shock on the 2002.

We gotta talk. :confused:

James · May 22, 2003

Originally posted by bscottr
We gotta talk. :confused:

When somebody says this to you, it usually isn't good news :thumb:

bscottr · May 22, 2003

Originally posted by James
When somebody says this to you, it usually isn't good news :thumb:

LOL...nah, just want to talk about shock improvements.

Well, maybe that is bad news. :)

flynbryan · May 22, 2003

Scott I'm definately interested in discussing this w/you as well. Us cheap skates need to stick together. ;)

James · May 22, 2003

Originally posted by flynbryan
Us cheap skates need to stick together. ;)

I like to think of it as "cost conscious" or better yet "inquisitive"

flynbryan · May 22, 2003

:thumb:

bscottr · May 22, 2003

Originally posted by James
or better yet "inquisitive"

Yup...that's it. :thumb:

For whatever reason there are some things that I couldn't care less how or why they work. For other things I want to know as much as possible. These usually involve things having to do with dirtbikes.....imagine that! ;)

flynbryan · May 22, 2003

I have that same interest. The more I learn about suspension the more I'm inspired!

marcusgunby · May 22, 2003

The strangest thing about suspension is that when you are convinced you know something(anything) a problem turns up that throws all your knowledge/testing in the bin.The only thing i know about engines and suspension is that you have to try everything(including stupid stuff) to know-they dont follow theorys.

scotth · May 23, 2003

bscottr,

Ordered the mid valve conversion parts today from Race-Tech and should have them before next weekend. I already installed the new base valve setup, and will try it this weekend. Do you remember if you could feel the effect of removing just one of the 24x10 shims at a time or did you have to remove 2 or 3 to really notice a difference?

TNT on Monday is a possibility; I think it is about 3 1/2 hours from Raleigh. :(

Thanks
Scott

bscottr · May 24, 2003

Originally posted by scotth
Do you remember if you could feel the effect of removing just one of the 24x10 shims at a time or did you have to remove 2 or 3 to really notice a difference?

Scott,
Removing one shim (24x10) didn't provide much of a difference for me. At first I didn't want to go with dramatic changes due to lack of knowledge on what the effect would be. It was only after seeing the 2000 125 setup did I realize I could make significant changes and still be OK. So yea, removing 2-3 shims is when you'll really start to notice. Just make sure you don't reduce the stack height so much that you don't get proper clamping pressure from the clamping shim and nut.
One point as a heads up; after you convert your mid-valve don't be alarmed by a slight "clicking" sound when going over small chop or braking bumps. It's the mid-valve opening and closing very quickly. At first I was concerned and then a bud told me he and a few other folks noticed the same thing. :eek:

Originally posted by scotth
TNT on Monday is a possibility; I think it is about 3 1/2 hours from Raleigh. :(

I hope it works out for you! If you want to ride with a lot of great folks come on down. Our BS sessions are usually as fun as the riding and we can do some tuning. :thumb:

flynbryan · May 24, 2003

I come just for the BS.......its the one thing I'm pretty good at keeping up w/these guys at. ;) Riding w/them is just extra incentive.

scotth · May 28, 2003

Weekend testing:

After I installed the forks, I adjusted all the suspension settings back to stock. My first impressions riding the bike were, the forks felt vary plush. This setting would be great for trail riding.  I wish had these settings on past trips to WV, It would have been much more enjoyable, not getting beaten-up allover that rocky terrain. :)

After a couple of laps on the local MX track, I could tell the forks needed to be stiffened up a bit, 2 clicks more on the compression did the trick. The external adjusters defiantly now have a bigger effect on tuning. Previously, I could hardly tell the difference of 2 clicks, now it is vary noticeable. Before I install the mid valve check plates, I am going to experiment with the bike like this for a while. :thumb:

Thanks to all for the info.
Scott

 

bscottr · May 29, 2003

Good news Scott! :thumb:

craig-s · Jul 13, 2004

All I'd like to know is the type of oil and how much for a KDX250SR with a 200lb rider

2002 KX250 re-valve for woods

scotth

jaguar

bscottr

JTT

bscottr

flynbryan

dbrace

scotth

James

Lifetime Sponsor

bscottr

James

Lifetime Sponsor

bscottr

flynbryan

James

Lifetime Sponsor

flynbryan

bscottr

flynbryan

marcusgunby

scotth

bscottr

flynbryan

scotth

bscottr

craig-s

Similar Topics

2002 KX250 re-valve for woods

Lifetime Sponsor

Lifetime Sponsor

Lifetime Sponsor

Similar Topics

Privacy & Transparency

Privacy & Transparency