KDXRIDER.NET

It's been mentioned a few times, most hybrids are not AS comfortable when putting around at low speed compared to the KDX.
I did notice the same problem last week end when following slower riding buddies.
The rear was not so bad (has gold valve), but the front end is rather harsh even though both my clickers were full out on soft.
Seems the big problem is in the slow speed compression.

I'm thinking of changing the stack to 24 21 19 17 14 13 12 11 removing most of the 21 and 12) and stacking them from biggest to smallest like an inverted pyramid.
What do you all think?

I can't figure out why it doesn't simply go from biggest (24) to smallest (11) already?
I don't know enough to say if there is a valid reason or not.

I'm not going to touch the LSR low speed rebound just yet (wanna try that 1st + I'm hoping to remove the base valve without taking the forks apart...)

This is what the shim stack look like when I took them apart during my build, you can see the shock in my bike profile.


FORK
shim stack
Base Valve, LSC:
nut
cup
spring
washer sleeve
piston
21 x 4
12
24
21 x 2
19
17
14
13
12
11
18 thick spacer

cartridge:
HS Rebound
nut
thick washer
11
12
14
17
20
23 X 3

piston
HSC
20
25 x 3
22
20
17
15
12

LS Rebound
15 X 2
17
20
22
23 X 3
20
o ring
15 (to keep correct height of the stack)
cup
rod

What thickness are the shims in your forks? Have you removed the bladders?

I've been messing around with the shim stacks in my '04 forks and have made progress with the base and mid-valve changes. From the factory, my base valve had a lot of .15 shims, which I've been told have no place in a fork.

I ordered some .10 shims that will be in tomorrow. The approach I'm taking is leaving most of the low speed shims in place to keep the fork up in the travel and help with g-outs and the occasional jumps. But I'm really going to soften up the high speed to make rocks and roots more manageable. Hopefully I'll be able to test this base valve stack over the weekend.

I also bought the shim restackor program. It is nice to be able to test out shim stack changes without opening the forks up each time. I think I paid about $30 for it, it has already been well worth the money.

Send it to me Ted....


Just kiddin'!

bladders were removed as for thickness, can't recall, I think they were .10.
Yours are 04 mine are 02 (and 01 on the kdx)
Just looked at shim restackor program online, never heard of it, looks really cool. Might have to get it, and play with it instead of paying someone hundreds of $$$ to tune my forks.

Man, info like the shim restackor program is why I like this site! I had no idea it existed, looks great, and the price is more than fair. Too busy on other projects right now, but will use it in the future for sure.

Indawoods wrote:Send it to me Ted....


Just kiddin'!

I'll be happy to run some scenarios for you. What I don't know is if your '03 forks have the same valves as my '04's. If they are different, I'd need some measurements of the ports and such.

Sounds like your spring rates are wrong.

Tedh98 wrote:

Indawoods wrote:Send it to me Ted....


Just kiddin'!

I'll be happy to run some scenarios for you. What I don't know is if your '03 forks have the same valves as my '04's. If they are different, I'd need some measurements of the ports and such.

Not familiar with this program. Does anyone know if it will run a Mac with Pages (Excel compatible)? Could be a possibly if I knew enough about suspension mods.

G22inSC wrote: Not familiar with this program. Does anyone know if it will run a Mac with Pages (Excel compatible)? Could be a possibly if I knew enough about suspension mods.

I don't remember seeing instructions for Mac's, but since I don't have one I wouldn't have been paying attention. You'll need to contact them to find out for sure.

I got my .10 shims and finally got around to putting them in. I've got a series of 6 - 12" rocks in my backyard that I do a little testing on.

The preliminary riding results are the best I've had to date. The biggest rock that I hit feels the best with this combination. It looks like with the weather and the Holidays I won't get to do serious riding/testing for a couple of weeks.

The basic changes I made were to reduce the float down to .3 mm on the mid-valve, remove a couple of the low speed shims on the base valve and replace all the .15 shims on the base valve with .10 shims.

Once I can really test this out and verify this is a solid combination, I'll post up the details.

any update Tedh98?

My forks are stiff as a board on the high speed stuff, roots, rocks, braking bumps, accelerating bumps, it's harsh. On jumps, low speed and woops they feel ok, no bottoming.
I rode in a rocky area last week (quarry), there was a lot of small bumps and pebbles and I noticed my fork was hardly moving up and down. My fork compression is out on full soft and I'm beginning to wonder if the valving is really the issue.
The front doesn't sag the way it should, I get hardly any (less than 1 inch). wrong fork spring?
The rear is good, sag numbers are perfect for my weight so can't figure out why the front would be so stiff and out of specs for my weight.
Any insight?

In the parts gathering process of my hybrid build I aquiered a 05 250f formerly owned by Dietrch with full procircuit suspension, trippleclamps and rear linkage when adding parts to 05 125 frame the biggest gain was the rearlinkage it seemed to even things out a lot more and helped in the way she corners

scheckaet - I've been keeping track of everything I'm trying to get these KX forks to be good in the woods HERE.

Have your forks always been stiff on the small stuff or is this something recent? Before spending money on springs or doing shim changes, I'd first check to make sure everything is in alignment on the front end. skipro3's procedure has been posted a couple of times here recently.

Do you know when the bushings and seals/wipers were last replaced? Rebuilding the forks and adding fresh oil could make a difference if it hasn't been done in a while.

When I was trying to find out what to do with my '04 forks, most of the information I found about KX forks was for the '99-'02 forks. Seems most people benefited from disabling or removing the bladders in those to get rid of the harshness. This is a nice thing to try b/c the only cost involved is new fork fluid.

My experience has been limited to only these forks, so take what I'm about to say with that in mind. A lot of people remove several of the big face / low speed shims to try to soften their mx forks up for the woods. While that does soften the entire stack, my experience has shown me that it doesn't really help the harshness. With not enough low speed dampening, the forks will ride lower in the stroke, keeping the harshness. Plus you tend to bottom out easier on not very big jumps or g-outs.

I think and hope that I've found my final shim configuration. I've got slightly firmer low speed than stock, but my high speed on the base valve is softer. And the mid valve is softer with a good amount of float.

I hope something in that long reply can help you out.

tedh, great write up on your site, will have to re-read it carefully.
I've done the alignment several time and doubt it's the issue. I'll check again to be sure.
I've had this issue since the rebuild of the fork when i did the hybrid. At first I figured it was because the seals and everything was new and needed time to break in.
I did remove the bladder but it seems improperly, i left the white plastic ring, always thought it was some kind of guide.
I wonder if this will solve the issue, always thought the bladder was involved in the mid-stroke harshness.
Need to pull the spring and check the rate, still convinced it's the problem.

Remove the valve for the bladders. It is under the spring retainer.
Tweek the valving, most gains come from the midvalve, and then go purchase some subtanks or better yet make a set yourself out of PVC for less then 50.00 and install.
You will love your forks!

I don't see many using subtank, must be a reason. I'd have to look it up though.

I've been looking into those and from the reading I've done, they don't work as well on the twin chamber forks as they do on the cartridge/open chamber forks. If there is truth to that, it might explain why you don't see too many of them.

When you read the reviews of people that use them, it sounds like one of those 'too good to be true' type of things.

Once I confirm I'm done with my valving changes, I was going to try to build a cheap set and see how they work. The one thing I'm not sure of is what type of valve to use. Of the companies that sell these, there are two types of valves. One restricts air into the tank but not out and the other restricts air both ways. I may just get both type of valves and test them out.

I may have missed something here but i thought the post was talking about the open cartridge bladder fork and not twin chambers.
You are correct the subtanks really do not do much for twin chamber forks.
They work great with the old open cartidge style fork including the blader forks.

hybridracing65 wrote:I may have missed something here but i thought the post was talking about the open cartridge bladder fork and not twin chambers.
You are correct the subtanks really do not do much for twin chamber forks.
They work great with the old open cartidge style fork including the blader forks.

I brought up TC forks b/c scheckaet mentioned he doesn't see many using subtanks. I believe you don't see them much since bikes made in the last 5-6 years use TC forks.

As I was researching subtanks, most of the posts were pre '05. They were really popular back then.

I'm slowly working on getting the parts together to build my own.

Sub tanks are now installed on my hybrid, the details are HERE.

I'm trying to go riding early next week to test them out.