[KDX200H] 97 KX250 fork

[ced64k]

Hi,

I'm looking for a simple solution for the USD fork swap on my 96 KDX 200. Here in Belgium KX 500 are fairly common but finding a fork alone it's not easy. And I prefer to don't do the stem swap to keep a fully working original KDX fork with triples as spare parts.

I'm planning to buy :
- a KX 500 lower triple 1998-2004 from eBay US
- a complete KX 125/250 1996-2001 frontend (fork, upper triple, wheel, brake, etc) here in Belgium.

For all these years it's a 46mm Kayaba USD fork.

So I'm right ? I will have all the parts needed for a direct swap ?

And what about the geometry with the longer KX fork ? Is it possible to pushed up the fork in the triples ?

Thanks :)

[KDXGarage]

1996 and 1997 KX125 / KX250 forks will fit those clamps.

Try not to focus on the diameter of the chrome inner tube, go with the outer tube diameter where it fits into the triple clamp.

For best results, the KX forks need to have the travel shortened internally with a travel limiting spacer installed.

[ced64k]

Thanks Jason. So I'll try to find this 96/97 fork.

Try not to focus on the diameter of the chrome inner tube, go with the outer tube diameter where it fits into the triple clamp.

Is there a database or something to know the outer diameter for each year ?

[KDXGarage]

No need for a database, just buy about every year fork and clamp off ebay like I did.

It varies, but some years are a one-year-only deal, and some are the same for 2 or 3 years. Some change the next year on just the top.

[ced64k]

KX 250 97 forks should be mine soon. But the KX 500 triple tree are VERY hard to find. Nothing on eBay. Nothing at french or uk motocross breakers. I'll have to bring myself to cannibalize my KDX stem with KX 250 lower triple…

[6 Riders]

Just buy another KDX lower triple and cannibalize that stem.

[ced64k]

Yes that's an option ;)

[motoracerx]

Soooo, these KX forks changed upper tube diameter almost yearly? wow.

[KDXGarage]

Not almost yearly.

Inner cartridges got bigger at times, outer tubes got bigger at times

91
92-95
96-98
99-01
02
03-08

that is for 125/250 upper clamps

91 is due to offset, not size, if anyone wants to get the HMMM moment

[ced64k]

- KX250 97 forks received
- KX125 97 triple tree ordered
- RB Designs spacer ordered

Now the wheel ? /invoke Jason
I can get a KX125 2000 wheel for a fair price, do you know if it fits the KX250 97 fork ? I have the axles for the 2 forks.

[KDXGarage]

I can not remember on the wheels. Maybe someone else can help on that. Sorry.

[ced64k]

I checked and 93-98 KX125/250 have the same reference for the front axle but starting 99 it's different. Maybe it's better to look for a 93-98 wheel.

[ced64k]

Finally I got all the stuff:

- KX 250 97 fork
- KX 250 97 wheel
- Stem swap made on a KX 125 97 triple clamp
- RB Designs stem spacer

Next step is to bring the fork to my local motocross shop. I would like a complete revalve/rebuild. But for the KDX/woods riding tuning, I'm not sure what I have to ask. I read things like shorten the fork, softer springs, etc. How can I know how many inches it should be shortened ? The bike is completely disassembled so I can't mesure it with the standard fork.

For the springs, when I try the Racetech calculator I choose Trail/Enduro, dirt novice, standard height, the recommended fork spring rate is 0.436 kg/mm.
For the rear shock the recommended spring rate is 5.402 kg/mm. Do I need to change something on the stock KDX shock ? A rebuild will be sufficient ?

[ced64k]

Anyone ?

[KDXGarage]

Measure the center of the axle to the top of the cap on the KDX and then on the KX, then report your results.

[ced64k]

Ok thanks Jason :)

[KDXGarage]

In general, KX forks are longer than KDX forks, so it throws the geometry off and if not pulled up super high, they chopper the KDX out.