Fork Swap Recommendation for Short Folks

[HeyItRuns]

Hey guys,

I have an E3 that I just got plated. My suspension is cooked. I hit some new England potholes at 50 and it tried to throw me into the other lane. I think it's time for new suspension, and it seems like it makes more sense to do a front end swap.
Im 5'8" in my boots and I was already planning on dropping this thing an inch. I'm concerned most mx forks are going to be long enough I won't be able to accomplish this.
Does anyone know of any forks that will work with the Amazon conversion bearing that are likely to be about stock length?

Thanks

[KDXGarage]

MX fork travel is generally about an inch more than trail bike forks back then. Just get them shortened 2 inches instead of 1.

Be safe out there.

[Chuck78]

That's good advice that KDX garage gave you there, but also, I would advise that the 1990s through 2009 or so at minimum KLX 300 forks will be a very easy bolt-on and are actually just a hair shorter than the stock KDX forks by perhaps 1/8 of an inch. Nearly all forks that you could find are going to be longer aside from that.
Another good bolt-on would be some Honda xr400r forks, however, unless you are about 160 lbs or more, you might perhaps find the spring offerings a bit on the firm side if you can't get anything softer than stock. 1997-1999 Suzuki DR350 & 350SE bikes came with virtually the same forks as the Honda XR 400R. They are 43 mm right side up Showa conventional forks with gold anodized tubes with silver aluminum axle lugs. They will slide right into your KDX triples although I would recommend 95-06 KDX triples over 89-92. You would need the XR400 wheel and axle, as they have larger diameter axles, which is a good thing compared to the stock KDX KLX axle that is very small in comparison to anything else modern, at 15 mm. Early KX and these XR 400 and DR350 last generation forks use a 17mm axle. Anything modern uses 20 mm or larger.

One other thing to consider, the motocross and modern woods bike forks will have at least 1" or 1.5" taller height with around 1" more travel than what the KDX has, so generally speaking if you buy a fork that's 1"+ taller but has 1" more travel, lowering it 2" would leave you with still roughly the same amount of travel as what the stock fork lowered 1" would have. Generally any fork lowering is going to require that you buy shorter springs if you can find something to the right specifications of inside versus outside diameter and correct length for your needs or slightly shorter (+ preload spacers), but not too short, as you don't want to bottom out the coils all against each other prior to the fork reaching its full travel.
Some older forks will have preload spacers of varying lengths, so you might be able to get away with running the springs currently in them or a different spring rate to suit but still stock length spring, just by removing the preload spacers and having the suspension shop make up the same length of spacer but one installed as a damping rod top out spring spacer which will lower the bike by changing or shortening the fork's fully extended position.

[billie_morini]

HeyItRuns,
I have a 1999 KDX 220 and a 2003 DRZ 400S. I'm short, old, and 153 lbs. I shortened the suspension for both of these bikes by 2 inches (50 mm). It is not difficult to do and is reversible. In addition to shortening the suspension travel, I got springs for my weight, how I ride, and where I ride. All in all, it was not expensive. Importantly, these changes increased my fun by 200%! It's so good that I wished I'd done it sooner.

[Chuck78]

HeyItRuns,
I have a 1999 KDX 220 and a 2003 DRZ 400S. I'm short, old, and 153 lbs. I shortened the suspension for both of these bikes by 2 inches (50 mm). It is not difficult to do and is reversible. In addition to shortening the suspension travel, I got springs for my weight, how I ride, and where I ride. All in all, it was not expensive. Importantly, these changes increased my fun by 200%! It's so good that I wished I'd done it sooner.

Those 2000-2024 DRZ400/DRZ400E (& 2002+ DRZ400S but not the cheaper internals '00-'01 400S) forks share the title with the identical looking 1997 - 1998 Suzuki RM 125 and 250 forks as being the best Woods forks of all time. They definitely need a revalve to be great, & resprung when swapping onto a much lighter weight compact chassis 2-stroke like the KDX, but a 49mm right side up "conventional" fork is an incredible thing for woods riding, although they are only 1.0 lbs lighter than stock '95+ KDX forks, versus newer closed chamber forks like the current 2019 and up Showa 49mm twin chamber forks on the CRF 450/250 (2017+ 450 & 2005+ CRF250), and KX450 (&2025+ KX250F) are 2lbs lighter than the stock KDX forks. I'm not sure about the late 2010s versions, but the 2017 and up 49 mm show a twin Chambers measure at least two lbs lighter than the stock KDX forks. The 48mm open chamber KYB forks take the crown at up to 4 lbs lighter than the stock forks while being substantially larger diameter. They weigh about the same as the 43 mm KLX 300 forks surprisingly, and are substantially better although there's KLX forks are a fantastic bargain upgrade for someone who weighs 135-170 lbs or somewhere a few pounds closer to the middle of that range, as then the stock springs are great and the stock valving is an upgrade over the KDX but a revalve can be done DIY for free to improve it further. They still flex a lot due to the KDX KLX axle size, but they don't flex as much as the stock KDX forks, so even those are a pretty nice upgrade for minimal effort.

[SS109]

I am (was?) only 5'8" and 147lbs. I'm running '06 KX250F Showa 47mm forks on my KDX220. I never have internally shortened them and just slid them up in the clamps to get it balanced out. I have no issues reaching the ground with the proper springs and sag.

[HeyItRuns]

Thanks everyone,

I ended up buying a front end from a 2000 KX250. I picked it because it was relatively inexpensive, was complete, and because I read this post and saw it would work:

viewtopic.php?t=26464&sid=627bc0232df2f ... b9257544a0

I bought these bearings, which I'm hoping are the right ones.
https://www.amazon.com/gp/aw/d/B0CKNY2C ... prod_image

I'm gonna replace the seals and figure out how to shorten them a little. I'm hoping they're a decent pick. I'm sure they're better than what I have now.

[billie_morini]

For what it's worth, I shortened front forks and rear shock on my KD 220 and DRZ 400S.

[HeyItRuns]

Anyone know how to internally shorten these?
I bought the Kit from Race Tech. It came with 2" PVC spacers and some washers. I also bought shorter springs. The instructions arent helpful and the QR code for the video that came with it doesn't lead anywhere.
I can't figure out where the spacers get placed.

[Chuck78]

Anyone know how to internally shorten these?
I bought the Kit from Race Tech. It came with 2" PVC spacers and some washers. I also bought shorter springs. The instructions arent helpful and the QR code for the video that came with it doesn't lead anywhere.
I can't figure out where the spacers get placed.

The spacers get placed under the rebound/mid-valve piston. They basically make the fork rest on the 2" compressed (from top-out) position as it's new maximum extension.

You're definitely going to need to drop the rear end as well. You can use 1" lowering links, but the real problem with those is that you now may risk using the upper chain roller as a bottom-out bumper when smashing the chain and swingarm/chain slider against it. 117mm (older models) KLX300 pull rods aka dog bones are the longest I'd go with links, and I'd recommend less. That will drop the rear end about 7/8" or so. Later KLX300 late models use 118.5mm links, and most KLX650 use 124mm but a few years used 115mm which is great for the KDX also. If 117mm links @ 7/8" or 24mm-ish lowering ride isn't quite enough, first try reducing the preload on the shock spring to get more rider sag when you are seated on the bike (easy option), or else rebuild the shock with a Race Tech Gold Valve kit (thank me later, the stock shock valving is trash for rugged woods riding) and install Race Tech sealhead lowering spacers in between the shock piston and the sealhead to drop the shock, maybe 3mm or 4mm overall (ride height lowering is 2.3x to 3x that depending on where you are in the suspension travel with it's rising rate linkage). Then play with the fork height in the triple clamps to drop the front end further to level the chassis back out to avoid poor steering/cornering traits that can happen if the front end is still too tall.
You'll need the longer linkage bolts for the pull rods from the KLX as well, as they are thicker links and need slightly longer bolts. The KLX250 uses the same 117mm links also. There are both aluminum and steel 117mm versions on both models depending on year. The bolts for the pull rods are specific to the link thickness, KDX is thinnest (shortest bolts), KLX steel 117mm links are thicker (longer bolts), KLX 117mm aluminum links are thickest by far (longest of the 3 linkage bolt options), so the bolts must match the suspension links they were matched with - best to buy the bolts with the pull rod links. Here's a deal for you on the fancy aluminum ones, very slight weight savings vs the steels but the longer bolts make part of that back:

https://www.ebay.com/itm/315711107613

That'll lower the rear almost an inch. Like I said, I never recommend going longer than that, 112.5mm stock KDX up to 117mm KLX300, that's the maximum I endorse lowering the rear with longer pull rods. They make KoubaLinks that are much longer, but that really messes with the handling and the suspension action considerably.


I'm not sure about the 2000 model year KX forks, but the 1996-1997 KX250 versions (same as my 1997-2004 KX500 forks) are around 1-3/8" longer than the KDX forks. You need the front wheel also from the KX or similar up through 2005. The 95+ KDX brakes should bolt right on, but the axle is specific to the 1999-2002 or maybe through 2005 fork, and specific to the KX wheels (or the 20mm axle more specifically) 1994-2005 or 93-05.
The KLX300 links should help you out a lot and leave it so you may only need to slide the forks up through the triple clamps 1/4" to level out the ride height to regain stock chassis steering geometry. if the rear is lower and front is noticeably taller, it will corner poorly at speed.

[HeyItRuns]

Thanks man. I already got spacers to internally shorten the rear shock. That seems straight forward. I'll see when I get there. Keep you posted.
Yeah I should have clarified, I have the forks most of the way apart using this video:

But I can't figure out how to get to the midvalve. I figured they'd have to go somewhere in there but it doesn't lend itself to disassembly. How do I take it apart?

[HeyItRuns]

If I'm right, it should go onto 46102 in this picture. But I can't figure out how to get to it because 44022 is in the way.
[

[Chuck78]

If I recall correctly, you have to get into the center cartridge assembly that the rebound piston rides inside of, and I remember having to drill out some staking that prevents them from coming apart if I recall correctly, only in the outer aluminum tube of the internal cartridge assembly. Do some digging on KYB mid valves for this era of fork, on here and thumper talk and maybe vital mx, and you will find what you are looking for. I may have a write-up bookmarked somewhere but have a busy day here.

[HeyItRuns]

Yeah, I looked through a few guides, but I'm still having trouble. I'll post them up here.

This person was able to get the rod out once he removed the keeper nut (92055A). I'm going to try that once I find a thinner wrench.
https://www.thumpertalk.com/forums/topi ... /#comments

This person has a post where he talks about drilling out several peened spots. That sounds similar to what you mentioned, but I can't figure out where to drill. I'm also hoping to avoid all that work if possible.
https://www.thumpertalk.com/forums/topi ... bly-guide/

Also, here are the Race Tech instructions of anyone is interested.
https://racetech.com/ip-fk-preload-inte ... open-cart/

[Chuck78]

This person was able to get the rod out once he removed the keeper nut (92055A). I'm going to try that once I find a thinner wrench.
https://www.thumpertalk.com/forums/topi ... /#comments

This person has a post where he talks about drilling out several peened spots. That sounds similar to what you mentioned, but I can't figure out where to drill. I'm also hoping to avoid all that work if possible.
https://www.thumpertalk.com/forums/topi ... bly-guide/

YES, that's exactly what I was referring to. Many of the KYB 46 OC USD forks require this... Post up pictures of your cartridge assembly and perhaps we can help determine if yours does.