KDXRIDER.NET

HeyItRuns,
your black spacer placement is similar to the black plastic spacer I installed in my 1999 KDX 220 forks. Also, there is a metal OEM spacer in my forks. My photos show before & after I put the black spacer on the rod. You can see where a spring is on mine.

Wrap some plumber tape on the threads before you put the rod back through the seal / bushing.

Update:
I reassembled the forks. I bought the wrong springs from RaceTech, so they just came in. I am working on the shock for now.
I'm rebuilding the rear shock and I'm going to lower it internally using the race tech spacers as mentioned by Chuck78 above. I used the guide from RaceTech (see link below) and measured the distance from fully extended to the length extended when I raised the wheel 1". It looks like it's about a 5-6mm difference.

https://racetech.com/ip-spls-lowering-spacer/

Update:
New springs from RaceTech came in. I installed them and used the included spacers to set the preload. It took me longer than I like to admit to decipher how to place the spacers using the surprisingly bad instruction sheet that came with the forks (see link on previous page).
Basically, I just needed to add spacers until the springs touched the fork caps (which makes free length = set length) and then measure out the number of spacers equivalent to the desired amount of preload (4mm according to their website). This ended up being a total of 5 spacers. For anyone reading this in the future, the spacers go at the bottom of the spring because if they don't, you can't attach the fork cap.

I then set to work on the shock. I used these two videos:
The first is kind of a general overview, but is really well edited.


The second has worse camera angles, but is specific to the kdx. It was good for some things but not others. More on that in a minute.


I was able to get just about everything apart. It was incredibly dirty and things were stuck that had no reason to be. The top video kind of shows how to disassemble the shock, but shows a different KYB shock with a different retaining ring. Ours use 2 overlapping rings that fit in one another. Mine were rust welded together and I had to hit em with a hammer a little. The cap that goes over the bladder was also a pain. I ended up putting a socket over the schraeder valve and using an even bigger hammer. I was able to pull the cap out with this tool, which I recommend.
https://www.amazon.com/s?k=atv+shock+tool

Then things started going sideways. I ran into 2 issues:
1) I didn't have everything I needed. I bought the parts to do this a while ago, and I thought I'd bought a kit. I didn't. I bought a seal head and bladder from All Balls. I realized after reading other threads here that I still need a new nut, piston ring, and piston o-ring. I bought them from ebay and they are on their way.
2) I also made the mistake of following the instructions of the second video step-by-step, and in the video he mentions that he did not remove the peening from the top of the piston rod and just chased the threads. This was a terrible idea. I put it in a vice and just used a big wrench to crank on it. I did in fact get the nut off, but it took with it the top 2 1/2 threads, which were left half attached at a jaunty angle. I had to grind off those bits as carefully as I could. The link below is a post from this site that has really good instructions on how to do this the right way if someone wants to see that.
viewtopic.php?t=25898#p224264
This is a Facebook post that has really good pictures of the process.


This is a picture of my piston ring. Note that it is in fact cooked.


This is a picture of poor piston shaft. Note the marring at the top from where I had to grind it.


Questions:
1) I have a snap ring that came with the new seal head, but I don't have a new one for the bladder. Do I need a new one, and if so, where can I find one? I've been looking at the diagram, but there is no part number.
2) Does that piston rod seem saveable, or should I just call it and try to scrounge up a new shock?
3) Does the nut really need to be a KYB one?

Thanks for the help in advance.

OUCH!! I did that the first time I worked on one, but that was before Youtube and forums.

I would try to find a thinner bottom plate / washer. That would move the nut down. A KYB nut has the metal portion to catch the threads. 25 foot-pounds of torque and red Loctite.

Got a little bit done last week.
I managed to remove the old piston ring. I'm including a picture of it below in case anyone wants to see what a really worn one looks like.



I knew it was in need of replacement, so I just broke it in half using a pick rather than trying to save it. I bought a new one and a new o-ring and put the piston in the freezer for later. I'm going to try the technique noted here:



I also did my best to save the threads on my piston rod. I used a two-piece dye I bought off of Amazon and some cutting oil and was able to make surprisingly good progress in that regard. The two pieces of the dye fit around the undamaged threads and by working it off of the rod, I was able to salvage most of the damaged parts. Here are the pictures of the progress.




As you can see, the top threads aren't perfect, and when I thread my new nut on, it still feels similar to cross threading until that portion is cleared. The new nut is not a KYB spec replacement, and it's a little shorter than the original, but I'm hoping it will hold on with enough red locktite.



I still am trying to find the snap ring that holds the bladder cap in place. I've been searching high and low, but the diagram doesn't have a part number. I might just reuse the old one if I can't find it. This is the one I mean:



If anyone knows where I can source one, I'd appreciate the input. I've been looking at Technical Touch's website, but I'm having trouble deciphering it. I am planning on keeping the stock spring. RaceTech's website doesn't provide a replacement recommendation when I use their lookup tool. I think for the moment it will be fine for the light commuting and adventure riding I'm planning.

Sorry for the long post folks and thanks in advance.

HA HA. I did finally find someone who cut one of my mounting tools down.

The nut will be fine. 25 foot-pounds.

I would just reuse the clip.

KDXGarage wrote: 11:23 pm Apr 02 2026 HA HA. I did finally find someone who cut one of my mounting tools down.

The nut will be fine. 25 foot-pounds.

I would just reuse the clip.

Awesome! I've got the piston in the freezer and I'm going to try putting the band in hot water and sliding it on with some fork oil and a feeler gauge.

Thanks for the reassurance on the nut and clip. Nice knowing I'm not losing it.

Because I had some down time I bought a 2022 klx300 spring with 8hrs on it for $38 on eBay. I know the old klx300 springs fit and were a cheap way to get a higher spring rate. It looks like the new ones use the same kyb 44mm shock. I'm not sure if the length is the same. Spring rate is 5.6kg/mm.
I'm 185lbs without gear and the bike is a couple pounds heavier than stock due to the battery, skid plate, bigger radiators, fan, etc. It might be too much spring, but seemed like it was probably better than what I started with.

I think a 5.2 would be good for you.

KDXGarage wrote: 11:34 am Apr 03 2026 I think a 5.2 would be good for you.

Good to know. I'll bear that in mind for when I buy the correct spring.
This was just meant to be a temporary fix, and I was honestly curious to see if it would fit.

The forks are running .50kg springs, which was what RaceTech recommended, but also seems stiff. This might be because when I was using the tool I set it for "dual sport" use rather than "enduro" or "mx". We'll see how it goes.

I don't think you are way off on the fork springs. 46 may have been about right with the extra stuff. Try to compensate with the compression adjuster some.