Kdx200 with klx300 forks - tube height

[H Muz]

Hi all, whats a good starting place for fork tube height?

Top of the tube (below the cap) to the tripple clamp.

Currently mine is set to 14mm, which is where it was set when I got the bike, seems high?

Cheers

[bufftester]

Are you running the KLX triples as well? Standard setting is 5mm, 14 seems a bit high. The KLX and the KDX had the same caster and trail so you should probably start at the standard settings and see how it feels. Just a matter of loosening and tightening 6 bolts and could be done on the trail so you can get immediate feeback.

[H Muz]

Yep, has KLX triples, cool will start with 5mm, cheers.

[Chuck78]

The KLX forks are slightly shorter than the KDX forks, and have slightly less travel as well, so running them flush with the top of the triples instead of triples slud down 5mm on the fork tubes is better in my opinion. This is how I've ran KLX forks for several seasons, and the handling is great. These are good forks to swap to save 5lbs and get stock springs suited for a 140-180lb woods rider, with improved valving over the KDX forks stock. There are definitely better forks to swap, but the KLX offer an easy modest upgrade for lightweight riders. For heavier aggressive riders, I'd steer them towards 45mm RMX250 invetted forks or 46mm/48mm KYB or 47mm/48mm Showas

[H Muz]

Thanks Chuck, I'm in the middle at about 160lbs, so should be good to go at 0mm to 5mm.

[Chuck78]

The height of the tubes protruding above the triple clamps has very little if nothing to do with rider weight, and everything to do with chassis geometry / handling preferences.

Spring rates for both the fork and shock are the primary variables based on rider weight. Suspension valving may have some slight variances based on rider weight, but springs are the main variable that's selected based on rider weight.

[H Muz]

Thanks Chuck, yeh am aware of that, cheers.

[brademan76]

The KLX forks are slightly shorter than the KDX forks, and have slightly less travel as well, so running them flush with the top of the triples instead of triples slud down 5mm on the fork tubes is better in my opinion. This is how I've ran KLX forks for several seasons, and the handling is great. These are good forks to swap to save 5lbs and get stock springs suited for a 140-180lb woods rider, with improved valving over the KDX forks stock. There are definitely better forks to swap, but the KLX offer an easy modest upgrade for lightweight riders. For heavier aggressive riders, I'd steer them towards 45mm RMX250 invetted forks or 46mm/48mm KYB or 47mm/48mm Showas

Hey Chuck, do you know anyone who has put the RMX250 inverted forks on a KDX? What does it take?

[Chuck78]

I would imagine it takes a steering stem swap and triple clamp machining same as the RM250 forks, the triples look identical but the clamping diameters are different. I found a V-Strom DL1000 aluminum steering stem (non -ABS models, the ABS models have a steel steering stem that clearly does not look like silver aluminum but instead darker hardened steel) will work out pretty well after machining the raised step off of the lower triple clamp bearing seat area.

[Chuck78]

You look in my show of 49 mm fork swap thread for the right side up conventional forks as well as DRZ400 forks, you will see a picture of milling the bottom triple to knock off that extra raised portion for the lower bearing seat. Then swap stems or you might even be able to just machine the RMX stem lower bearing area to be cut down to the press fit bearing diameter (30.00mm) as opposed to just a hair larger the press fit into the triple clamp.

[brademan76]

You look in my show of 49 mm fork swap thread for the right side up conventional forks as well as DRZ400 forks, you will see a picture of milling the bottom triple to knock off that extra raised portion for the lower bearing seat. Then swap stems or you might even be able to just machine the RMX stem lower bearing area to be cut down to the press fit bearing diameter (30.00mm) as opposed to just a hair larger the press fit into the triple clamp.

Thanks I read through the first half of that thread before deciding it's probably a good bit too involved for me. If I owned and knew how to run a mill/lathe I'd be down to try all sorts of projects like that.

I think the easiest route for me is go with KLX forks/clamps and appropriate spring wt and maybe some gold valves. Since you seem to have majority of this information catalogued (or at least know where to find it), and I drown trying to understand the differences, please advise:
Are all years KLX300 (and pre '09 250) forks the same minus spring rate?
-As a 6'3" ~210-15# rider I understand I'll need a higher spring rate

[brademan76]

Hmm, after investigating some, stock spring rate on a pre '09 klx250 is .44. Racetech recommends a .45 fork spring for my intended style (single track/woods/enduro) and stats on that bike, which is appx 50# heavier. So, maybe the spring rate wouldn't be too far off?

[Chuck78]

Hmm, after investigating some, stock spring rate on a pre '09 klx250 is .44. Racetech recommends a .45 fork spring for my intended style (single track/woods/enduro) and stats on that bike, which is appx 50# heavier. So, maybe the spring rate wouldn't be too far off?

Use the spring rate recommendation for your swap recipient bike (the KDX), not the donor bike.

I'd be looking into '94-'95 KX250 forks in KLX triples personally, if I wanted a proven bolt-on swap that's not much taller than stock The KLX forks are just a hair shorter than stock KDX ride height, but ride higher due to better spring rates than the kdx's .35kg/mm (115-134lb rider).
I'm learning (see other recent posts about swap fork / front end weights) that Honda CRF250/450 steering stems and Yamaha YZ250 two-stroke & some years YZ450F / WR450 have stems which are the right height for the KDX.... And special conversion bearing sizes have recently become available to facilitate the swaps into the kdx frames.

[brademan76]

Hmm, after investigating some, stock spring rate on a pre '09 klx250 is .44. Racetech recommends a .45 fork spring for my intended style (single track/woods/enduro) and stats on that bike, which is appx 50# heavier. So, maybe the spring rate wouldn't be too far off?

Use the spring rate recommendation for your swap recipient bike (the KDX), not the donor bike.

I'd be looking into '94-'95 KX250 forks in KLX triples personally, if I wanted a proven bolt-on swap that's not much taller than stock The KLX forks are just a hair shorter than stock KDX ride height, but ride higher due to better spring rates than the kdx's .35kg/mm (115-134lb rider).
I'm learning (see other recent posts about swap fork / front end weights) that Honda CRF250/450 steering stems and Yamaha YZ250 two-stroke & some years YZ450F / WR450 have stems which are the right height for the KDX.... And special conversion bearing sizes have recently become available to facilitate the swaps into the kdx frames.

Ah I've always shyed away from the kx fork swap because of the stem swap, etc. Do you recall which KLX clamps are and arent compatible with those forks?

[Chuck78]

I believe all the KLX clamps are,but 2012 or so the bike got redesigned, but still likely the same forks. look up the steering stem bearing sizes and lower triple clamp part #'s over the years.

[brademan76]

I believe all the KLX clamps are,but 2012 or so the bike got redesigned, but still likely the same forks. look up the steering stem bearing sizes and lower triple clamp part #'s over the years.

Ok I found your other thread where you mention the early 90s kx forks with the KLX triples. Thanks for your research/information on this! The only thing that makes me hesitate is also having to get a kx wheel. Hub width probably totally different than kdx, so even if a guy used the KX axle and found the right bearings to fit in KDX hub, probably still wouldn't work...

[Chuck78]

The thicker axle is well worth it for rigidity. 93/94-2002 was 20mm axle, 91-92/93 I believe was 17mm.