2001 factory KDX forks

[Chopperpilot]

So I'm in the process of swapping 93 KX forks on my 2001 KDX using KLX 650 triple trees. I'll probably re-valve the KX forks depending on how I like them (I ride mountain bikes a lot, I'm learning dirt bikes ......). Anyway, I'm wondering what to do with the factory 2001 forks off my bike. I'm guessing they'd only be worth something to someone with an older model KDX that wants the latest/best conventional fork set up. The fact I live in the middle of Alaska (Fairbanks) would I assume narrow this down to about zero people. So I was thinking of cannibalizing the conventional forks for shims and such to re-shim the KX forks. I'm not sure if they use the same size shims or not, I put race-tec gold valves in my 96 KLX650R, so I have those factory shims left over as well. Opinions? thoughts? being relatively new to the KDX world, I don't want to tear apart a set of 2001 forks to find out later that everyone with a 1990 KDX wants these unmolested. But....... given the hug section on here titles 'fork conversions' I'm assuming it wouldn't be a sacrilege to just break these down for parts.

[KDXGarage]

Hi. Welcome to kdxrider.net. The "reverse bend" shims in the KDX forks won't be the same as the shims in the KX forks. You can just buy individual shims if need be.

If it were me, I would remove a few shims in the compression stack of the KX forks to lighten the high speed compression damping.

I would keep the stock forks until I was certain I had the KX forks set up well and would NEVER go back to the stock forks.

[Chopperpilot]

Thanks for the advice, sounds good. I can't imagine going back to the stock forks. I come from a mountain biking background and while I appreciate the intent of the fork set up on KDXs, and I'm also not a fast rider, I do not like the flex I feel in them. So we'll see. I'm waiting on a KX caliper so I can get the KDX back on the road, so when I replace seals on the other KX leg I'll take the shim stack apart and take a look at it. These are 93 KX forks so no mid-valve apparently. I'm also looking at getting a set of the KX base valving from ebay which would provide some more shims to play with stacks on. Should I take apart one of the KDX compression stacks so I could look to see about reverse engineering the stack on the KX forks?

[KDXGarage]

Correct. No midvalve on 1993.

The valving system in the KDX forks is an older tchnology, so it would not apply to the 1993 forks.

I would just remove a few shims from the KX base valves and see how that works before diving deep into the rabbit hole of valving tiny changes.

Fewer shims equals less damping. More shims equals more damping.

Thinner shims equals less damping. Thicker shims equals more damping.

Smaller diameter shims equals less damping. Larger diameter shims equals more damping.

[Chopperpilot]

Took apart the other 93 KX 250 fork leg to re-seal. Took apart the base valve, there really aren't much shims to move/re-move the stack is just this:
22 x .15 (x2)
16 x .10
14 x .10
then a clamp 11 x .25
and spacers 18 x .50 (x2)
I've built a 2 stage stack both for my gold valved KLX 650 and for a mountain bike set up. I think I'll take apart the KDX valves and see what they use.
I just took apart the rebound shims on the 93 KX fork and it is a 2 stage stack that's much more complex than the compression stack. The rebound stack is as such:
21 x .10 (x2)
15 x .10 (crossover)
20 x .10
18 x .10
17 x .10
14 x .10
I'll have to look up rebound feeling from MX forks...... almost no one talks about that.

[KDXGarage]

What is your weight in full riding gear? Are the fork springs in the KX forks the correct rate for you and your KDX?
The shims in the KDX forks are just ten 0.10 mm all the same diameter. There are some old posts with more exact info.

Was the post of the base valve peened over? I wonder if someone else has been in there before you.

[Chopperpilot]

I'm about 205 in riding gear, using my hand dyno and comparing to my KLX springs, and the KDX springs, I think they'll be about right. I'll see when I get it going (I replaced the soft springs on my KLX650R for something I liked much better). The post of both valves were peened over, but with 30 year old forks..... who knows if this is factory or not (I haven't found the factory setup online yet). You can get the the nut off without grinding/sanding the post down, so it's possible someone messed with it and still left the appearance of the factory peen job. What I did was to remove one of the 21 x .10 rebound shims, I then used it to replace a 22 x .15 compression shim. I did this purely from the idea that MX forks are too stiff. I'll give it a ride like that (when my caliper gets here) and adjust from there. I'm hoping that I'll hit a happy spot of a 1993 fork being designed around a slightly lighter bike, a much lighter rider, and me generally liking a slightly stiffer set up (spring wise especially) that what charts say is 'optimal'. If it's way off, I'll look at gold valves and ask Race Tech about springs. I wouldn't think fooling with the factory (if thats what this shim stack is....) shims will be worth much of my time due to the few number of shims involved. It looks like Kawasaki relied on the small holes in the base valve to control fork movement as much as the shims. If so, this would be a great candidate for using gold valves with their higher flow rates. I looked at the factory valves to see about drilling the holes bigger, or flipping them over (I read about that somewhere) to increase oil flow rate, but there really isn't room for drilling. Flipping them over would probably add a ton of rebound dampening due to the more restrictive holes and the check plate.

[KDXGarage]

I think you could benefit from stiffer springs. 0.39 is the stock rate on the OEM diagram. Modern spring rates are a bit stiffer. The lighter YZ250X comes with .44 for example.

I have read a couple of posts in here from people breaking the post when loosening the nut without removing the peening on KDX base valves. Be careful.

As best I remember, those have 25mm cartridges, so that is better than the old 20 mm cartridges.

I have not had mine open, but I do own a new set of those forks for my "I'm going to rebuild it one day" 1993 KX125:

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