KDXRIDER.NET

Well the seals on my 91 kx125 forks took a crap today. They're puking fluid like there's not seals at all! Surprisingly the front brake is flooded and still works perfectly!

So If i'm going to tear them down for rebuild I figure why not re-valve them since I've got some money this time!

Other than the race tech gold valves are there any other valving options and is there anything I should know or consider while installing the kit?

Thanks Guys!

I doubt there will be much need to fit the gold valve kit....save some money & just run 5wt oil ...I would purchase genuine Kawasaki bushings & seals rather than cheap copies

I run 5wt now i found the servi kit from kyb on amazon
I was thinking about the gold valves for the tune ability but may or may not get them

Read up on suspension and make some shim changes yourself. There is no midvalve, so just a few shim changes are all you have to worry about.

Less shims = less damping
more shims = more damping

thicker shims = more damping
thinner shims = less damping

wider diameter shims = less damping
narrower diameter shims = more damping

I have had a set of 1991 KX125 forks apart before. They are not too complicated. I would skip the Race Tech Gold Valve for those forks. Unlike the KDX's with the inverse shim assemblies, your forks have "normal" piston and shims.

I will have to strip them down again i was thinking the base valves didnt have much in the way of shims ill post some pictures tonight if my wife will let me work on it

Jason can you explain what a mid valve is i thought these had midvalves but i must not be thinking of the right component they have a piston on the base valve and theres a second piston that is attached to the dampening rod that i had thought was the mid valve?

KX forks did not have a midvalve until 1995 KX125 / KX250. The rebound piston / band / valving is at the end of the damper rod. On the 1995 until whenever KX forks, the midvalve is on one side of the piston and the midvalve is on the other. It moves through the cartridge. It will have some "float" (another word to look up and rad about for years) and that is the distance where it will have a gap on top of the piston and like other piston / shim arrangements, it can be tuned.

The rod going down forces the oil into the base valve, so mostly, just worry about the base valve those forks.

I see hmm.. so are you saying I should play around with the shim stack on the rebound piston?

I got one fork torn down last night and all it has on the base valve is a check valve on the bottom (1 shim on a spring) on top the piston is open

I've been trying to read up on forks and suspension tuning if I'm understanding these forks and the midvalve/cartridge forks wouldn't installing gold valves essentially turn these into a midvalve type setup?

KDXohio wrote:I see hmm.. so are you saying I should play around with the shim stack on the rebound piston?

Those would be rebound shims. There is just a check plate on the other side.

KDXohio wrote:I got one fork torn down last night and all it has on the base valve is a check valve on the bottom (1 shim on a spring) on top the piston is open

Does it not look something like this??

There should be some shims on the bottom side, as the oil is forced downward.

KDXohio wrote:I've been trying to read up on forks and suspension tuning if I'm understanding these forks and the midvalve/cartridge forks wouldn't installing gold valves essentially turn these into a midvalve type setup?

No. Gold Valves are for compression at the base valve only, as seen in the above picture. The rebound piston is where midvalves are located. One side is valved for rebound and one is for the midvalve. It looks like a shock piston with valving on each side. Yours just has a check plate on the non-rebound valving side.

Ok much easier to comprehend with everything apart I was not remembering these forks correctly I thought the rebound piston had a stack on both top and bottom which as you said it does not same set up as the base valve...

The compression holes in the piston on the base valve seem very restricted I suppose I could start by just trying to open those up. My complaint with these forks is high speed compression I've ridden a lot of rocky trails lately and the front end goes all over the place it wore me out fast.

I've never done any valving and I don't want to do another front end swap as I think the next move will be a hybrid into a newer 125 chassis but that's a few years away

measure the diameter and thickness of the shims shown in the picture that are on the top of the piston (in the picture)

From top to bottom
Diameter then thickness
18mm. 0.51mm
18mm. 0.51mm
10.95mm. 0.25mm
13.95mm. 0.12mm
15.95mm. 0.12mm
21.95mm. 0.12mm
21.95mm. 0.12mm
Piston
Check valve

Top two i assume are just base plates?

Yes, don't worry about the 2 thick ones.

Had someone worked on them before? Was the peening already filed down?

You only have 5 shims, so that is not much to fool with. I would say take out one of the 22's. If that does not do it, then buy a 15 and a 17 to replace the 14 and 16?

No i had to file it down where can i buy shims?

The last time I bought some I used MX-Tech. They sold me just a few and only charged around $6 for shipping instead of the $16 or so it says on their site's order page, as it fills in UPS instead of a little USPS envelope. Call and talk with them.

That is a weird stock configuration compared to a few years later.

Those are 8 mm inner diameter, correct?

You are going to have to take some out and / or buy some larger OD ones. You are already at .1 mm on thickness. Some combinations of that are your options.

I've been messing around with them all week I ported the pistons and removed 1 22 that seems to have made a big difference. I don't have much in the way of obstacles to attempt in my back yard though so stay tuned!
I'll be taking it out a couple times this weekend as long as the weather cooperates!

Also I did buy the gold valves but have not opened them up if the modified stockers work well i'll send these back!

Good luck with it.

This is one of the compression pistons I ground the ports with a carbide bit and a dremel then did the finish work with some very small hand files the picture is before I filed it

Here is a comparison of the Stock(far left), Ported(middle), and race tech Piston.

I rode Saturday, Sunday and Monday and played around with the clickers and shim stack all weekend I forgot to bring the paper with me to work that I wrote my final shim stack on but here is a picture of what I started with for Saturdays ride. Left is the stock shim stack, I went to a two stage shim stack instead of the factory single stage. My Initial shim stack seemed a bit stiff so I change a couple by Monday.
I'm running 5wt Gold Spectro fork oil with the compression clicker at 12 and rebound at 14 and the front end floats over every whether its a rocky creek bed or a hill full of tree roots or even 60mph over a rough straight away. definitely worth the effort.