My take on the KX fork conversion

[krazyinski]

I have just about got my bike back to right just need softer springs. The OEM forks I had were valved and sprung for me. The main difference is even with the KX forks up in the trees the front is lighter and higher with springs not rated to your weight there can be some geometry issues that effect handling.

The OEM forks had the right amount of sag and less travel putting more weight on the front tire making the bike feel well planted in tight stuff with out having to move much of your weight around, making a great lazy trail rider bike.

The KX forks are like any other mod, you have to get out on your local trails and spend a little time tuning the suspension. I spent a lot of time setting and adjusting the sag and fork hight in the clamps to get the bike tracking true.

With the KX forks I found that you can put all your weight up on the tank with a hand full of break and really slam through some corners. faster comes with a lot more movement of weight distribution on the bike.

Some rider adjustment is or will happen to get used to the KX forks. With the forks I tend to go faster so more attention has to be paid to riding form.

I do all my tuning on a five mile loop of tight twisty sandy trails some steep 40ft up and down hills laden with rocks,ruts and roots, short deep sand open sections with 5-10 2ft woops and deep sand berms. never fails for a shake down run. keeping track of time and speed with the trail tech computer helps.

Just my two bits after riding in perfect conditions today.
nothing to blame it on today. but me

[Indawoods]

I agree... Too stiff of springs will leave you very light it the front... get the right springs... better too light than too heavy in my book.

[IdahoCharley]

Not that it is a real fix for either too light or too heavy of fork springs but adjustment of your spring preload may help you get the bike handling better. Too heavy of springs - back off the preload. Too light of springs - add some preload.

[Indawoods]

Charley... enlighten me on how to adjust the preload on my 03 KX forks. From what I can tell... it is what it is....

[Colorado Mike]

maybe spacers?

[Indawoods]

That would add more preload.

[Colorado Mike]

well yeah, unless you turn them over..

I need to start reading gooder.

[krazyinski]

I would like to know if any one with the KX forks would check the trail and wheel base.
and let me know what it is. to check trail I set the bike on its wheels under its own weight , measure using a plumb bob from the axel to the ground marking the ground, then using a laser or straight edge measure the center of the steering stem to the ground at the same angle, mark the ground and measure the distance. for the wheelbase I measure from axel to axel center. This is with race sag set at 4"

mine are: wheel base 57" to get inches from mm( mmx0.03937=inches
trail 3 3/4"


PS: I am a stay at home dad with three boys all under 5 years old, with no job and lots of time on my hands while the kids are playing, cause all I do is watch and put out the occasional fire, my old brain still wants to work and the bike sits in the garage, I can get carried away with details.

[IdahoCharley]

Charley... enlighten me on how to adjust the preload on my 03 KX forks. From what I can tell... it is what it is....

Don't you have any spring spacers between the fork spring and cap? (washers are usually of a plastic type material and longer OEM factory spacers usually being metal) Function of spacers is to take up space. P/N 92062 on the Ron Anyers microfiche - Indicates a spacer.

Checking preload: Remove the spring spacer(s) from a fork leg and then reassembly the rebound rod to fork cap. Extend the fork rebound rod and measure the free distance between the top of the spring and where the spring seats. A spacer that just takes up this free space would give you a zero preload. A spacer that takes up this free space AND is 5mm longer would give you a pre-load of 5mm. My thought is that generally you want to run somewhere between 2-15mm of preload on the KYB and WP forks.

P.S. I have seen forks without spacers from the factory but normally they do have spacers IME.

[Indawoods]

When I had mine apart... I don't recall seeing any spacers at all and it did have preload.

One way to get around this I guess is, buying maybe .38 springs, cutting them down and adding the spacer to adjust preload. But it seems like allot to go through just to get some adjustability.

***EDIT***

I checked the fiche... your right Charley!
I will have to get them torn apart soon so I can test ride it after my revalve. I will check for the spacer...

[krazyinski]

well after a good 100 miles on the KX forks and days of reading/ study of suspension action and reaction. I have had it !! with the .43 springs they are just two dang stiff for my liking, I cant get rid of the head shake , reading about this says two much compression damping,or to stiff of springs can be the cause. so I ordered a set of .40 for the forks from MX-tech. hope this helps. I have always had a soft suspension set up so I am not experienced in the stiff suspension set up.

[AZRickD]

If it helps, the .43s in my '98 forks are working fine at my 185 (not including gear) weight.

I have a WER dampener set on #3 and it went over jeep trail whoops at (for me) high speeds.

No shake.

That's not to say that I categorically endorse the .43s in front or the new 5.2 in back. I'm not savvy enough, yet, to speak to it.

Rick

[Colorado Mike]

my bike shook like a .. well, like a big ole shakey thing, with stock super slinky springs, and stiffer ones. I put the Scotts damper on it and my troubles were over. It made me quite a bit faster too. Then I put the KX forks on and those are very confidence inspiring.

[krazyinski]

I am running a wer damper on mine, If i lower the forks it gets twichy with the forks raised the front is two light, there is no preload on the .43's so my guess is not enough static sag plus the decrease in trail it makes the front feel bouncy and not well planted at times. if I run fast into a corner and brake late shifting all my weight on the tank it stays planted. but on high speed corners it feels skidish. new springs should help.

[AZRickD]

Yeah, sounds a bit too boingy.

Have you tried the KX to KDX re-conversion?

Rick

[KDXer]

I have a WER dampener set on #3.

What do you mean by #3 ?? I have a WER but it doesn't have any numbers to set the adjuster to, it only has a brass knob with a centre punch on it.

[canyncarvr]

The '03 fiche indeed shows a spacer.

I don't recall this being mentioned before, indeed, it seems it wasn't known to even BE there.

Not all the KX forks have such a spacer that can be trimmed for preload adjustment.

Take a look at the first pic in the KYB service sticky. No such spacer. My '99s have no such spacer.

Indeed, it is what it is with my forks. At least with the OEM length spring. There are other springs that fit just fine, a tad shorter, that you could MAKE a spacer for.

I was headed that way awhile back..have kind'a forgotten about it.

[IdahoCharley]

Krazyinski - You might want to try dropping your oil height 10-20 mm (increase your air spring/air gap). This may help the problems your experiencing with the KX front end. Then ensure your rebound settings are not too fast in the forks.

[canyncarvr]

Re: 'rebound'

Amen!

That skittery feel you mention is something that may be resolved with only a click or two 'more' rebound.

'#3' I would suppose refers to the number of 90º arcs the brass knob is moved and that from 'full tight'.

From 12:00 'o-clock to 9:00 'o-clock being 'one'

Oh..that's 9 'o-clock in the PM of course.


(Hey! Thass'a JOKE son, don't 'ya get it? I made a funny, son, and you're not laughin!!)

[AZRickD]

Crapola. I can't remember what I meant by "#3."

Maybe it was 3 turns from full soft, with 4 turns being maximum, or 75% of max.

Rick