'90 KDX200 to '92 KDX250 forks

[criggs9901]

Recently came up on a set of forks from a '92 KDX250 for super cheap, figured I'd get them and throw em on the 200. I know they aren't as much of an upgrade as the KX forks, but the person riding this bike really doesn't need the KX stiffness, plus the deal was too good to pass up. The only problem is that I can't find much info on this particular swap. Spent a few hours scouring this site, so I hope I don't ask any repeat questions here. Does anyone know for sure if the stem needs to be swapped, or will the one from the 250 work? Also does anyone know for sure if the caliper positioning is the same? I did swap the wheel over and confirmed it does fit nice and centered, and the 200 and 250 share part numbers for the brake caliper, but I couldn't tell if the disc lines up properly yet. Also, last thing, is there a particular guide I should look up to rebuild these forks? Never done them before, and I'd rather not buy a service manual for the 250 just for the fork service.

I'll be swapping and mounting everything this weekend to see what happens, just hoping to have as much info as possible when I start tearing into it. Thanks so much, guys.

[KDXGarage]

The clamps will swap right over.

Do you not have any fork guards?

I am not sure on disc compatability. I know you can't use a 1989 - 1992 KDX200 caliper, as it won't lt up to the hanger (caliper bracket).

There is a KYB fork service article in the sticky threads in this subforum.

[criggs9901]

Awesome, thanks so much for the info. It didn't come with guards, but I have a set on the way. The brake situation definitely has me confused, because the part number I looked up showed the same for both bikes, but everyone says they don't match. Guess I'll find out this weekend =P.

[david]

The brake situation definitely has me confused, because the part number I looked up showed the same for both bikes...

You didn't look up the complete part number
'90 200 43041-1312
'92 250 43041-1427

[KDXGarage]

The number on the diagram is the reference number, not the part number. A part number is 12345-6789, not 12345.

Stock brake hose routing on the KDX250 is a lot different than the current setup you have. Look at the online diagrams and some various KDX250 pics online. A line runs up under the fork to a hose.

[criggs9901]

Yup, you're right, I did some more checking last night and I think I just got some numbers confused. Looks like I will have to at least get a caliper, and probably a brake line too.

[criggs9901]

So here's what I've discovered about this swap so far. The E caliper will mount on the 250 forks, but the piston sits further forward than needed and won't allow the wheel to slide all the way in.


I ended up finding a used KDX250 caliper on eBay, got it in yesterday and mounted it up to see how the wheel looked. Everything bolted in fine, the caliper now lined up with the wheel, but it sits slightly too far inward for the original E wheel, causing the brake rotor bolts to just barely rub on the inside of the caliper bracket (different offset on the rotor? Different wheel spacers? Hard to tell, the wheel seems to be perfectly centered).



During some research, I came across a thread on this site of someone who swapped KLX forks to his E series and was able to use the original front wheel with some caliper bracket modifications. So I took the bracket to work this morning and performed the necessary mods. Didn't get a chance to mount it up yet, but will be doing that tomorrow, so I'll let ya know how it goes. As always thanks so much for the info.

[KDXGarage]

Good luck on it! Thanks for the "try it and see" info!

[criggs9901]

Okay so that first mod was close but no dice. The brake disc bolt still rubbed slightly on the inside of the caliper bracket. Brought it back to work, took another 2mm or so off the entire inside surface of the bracket, and now everything seems to be fitting right. The wheel is centered, and the disc sits as perfect as I can tell in the caliper. Going to give everything a good cleaning and swap it all over this weekend, I'll know for sure once everything is bolted up and brakes are fully installed and bled. If everything goes smoothly all I will need left is to make some kind of bracket for the brake line on the left fork guard. Not sure what I'm going to do there, yet.





Also I'll need to replace the axle. Having a really hard time finding one for these forks. The old one will work, but not exactly how it's supposed to. I'll post pics of that next time I get the chance.

[criggs9901]

Swapped everything over this weekend. I spent more time trying to get the master cylinder screws out of the cap than I did almost anything else. The triples and forks bolted up nice and tight, the wheel sits center, and the brakes fit and function perfectly (had to mount the line at a slightly weird angle, but it works fine). I still need to make a bracket for the lower brake line holder (I have the line zip tied in place for now), and I still need to get a proper axle for it. Also may need to move the forks up in the clamps a little more since they are an inch or two longer than the originals, but ran out of time today so I'll get to that later. Other than that it's fully functional.








To do the swap all I needed from the KDX250 donor were the Forks, fork guards, triple clamps (with bearings), and brake caliper. I was able to use the original E wheel and spacers, brake line, and master. Really happy with the outcome so far, can't wait to see how much of a difference they make.

[criggs9901]

Gave the bike a good wash the other day and snapped some better pictures while I was at it. Got a new phone, thought I'd give it a try. I figure at least the lighting is better =P.

[rungrandpa]

Did you notice a difference in the handlebar position since the clamps are straight up? Have you ridden enough to give a performance report?

[criggs9901]

Sorry for such a late reply, missed your question somehow. If the bars are further forward it's not by much. I've only ridden the bike once since the swap, last near in late November (I missed the entire winter riding season), but the handling definitely seems improved. Not a huge difference, but it feels more stable over the whoops and rough stuff at high speed, and it feels more responsive when cornering. I can't say for sure exactly why, if it's a bar positioning thing or if the slightly stiffer ride is the cause as I never got a chance to really push the bike hard before the swap, but I feel noticeably more comfortable on the bike for sure. Still haven't rebuilt them, went through a move in april so haven't had a chance yet, willing to bet they'll feel even better with fresh, full oil and bushings/seals. Honestly for the money I spent it was worth it for aesthetics alone, haha. This bike handles so good that it has inspired me to get Desert suspension valving done on my RM250.

[doakley]

Just looking at how you've got your front brake cable attached to the fork guard. You might be surprised how damaging those zip ties can be on the cable over time. I picked up a piece of aluminum "L" stock from Lowes Home Improvement and used it to make a small bracket that I then pop riveted to the fork guard. This let me use the standard cable clamp from my 220 forks. Just a thought.

Bracket 2.PNG (605.25 KiB) Viewed 7570 times

[criggs9901]

It's not zip tied anymore, I have it routed behind the guard along the groove that's intended for the under-the-fork style brake line that came on the 250. I actually made a bracket like that, but had a hard time finding a place to mount it on the 250 style fork guards because of the aforementioned design. Can I run a more traditional type of fork guard on these forks? I'd much prefer to have mine mounted with a bracket like yours.