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Hey all looking to swap my front fork springs from a stock 1990 E2 KDX which from what i can tell would be 470mm in lenght and .32k weight looking to throw a set of 1998 H KDX springs in which are 470m length and .35kg are these just a straight swap or do you have to make spacers or any other mods ? from what i can tell they should just be a straight swap any ideas would be appreciated..

Sorry mine are .30kg rated are these the same length as the 98H springs thats what i mainly need to know

I did it!

No they are not the same length. You will need to make new spacers with pcv scedule40 tube.

I was like you...my bike came with .30kg then I installed .35kg kdx220 springs. Thanks to IDAHOCHARLEY

This was not correct for me so now I have .40kg hondaXR400 2001 springs in my forks and I am happy!

I weight 190lbs.

You'll have to make new spacers out of PVC like kdxquebec noted. Start with the .35's, they will make a large improvement over your stock .29's. If you need heavier springs after that you can move upto the XR400 springs.

Hey Btw, if you or someone else need .35kg kdx220 stock springs I have a pair for you.

Even if you get the same rate springs they may not be the same length.

Even if you get a pair of XXkg/mm springs the two springs may not be the same length.

Figure the desired preload spacer for each fork individually.

Of course...this gets back to a main gripe of mine. WHY fill your downtube with steel (spacer) when its function is to SUSPEND the motorcycle?

Which is why I used a 520mm length spring..but whatever floats your boat!!

Oh...and why use a 30+mm preload? If the spring rate you have chosen is so far off as to require a 30+mm preload for a proper sag, maybe you need a different spring!

But...boats, floating and all that stuff............

Cheers!

I am putting KDX200 Springs in not 220.. does this mean they would be the same length? soon find out when i compare them to my own..

I'm sending my old conventional springs to Spawn to put in his 90 model.

So would they need to be longer spacers or shorter. I couldn't find any schedule 40 pvc over here either. I got my stock spacers cut down when I installed XR springs. Also what oil weights and height would be recommended ??

Also does anyone know the differences in front ends between E and H models ?? Can Spawn use my complete H model forks legs to any advantage or are they the same as his 90's ??

Any help is greatly appreciated...

Cheers,
Trev...

Trev your H series fork legs would be a huge upgrade for Spawn's 90 KDX. They are a cartridge valved design instead of a damper rod fork like the 89-92 KDX's. He would have to get a H series brake caliper, front wheel and axle though to finish the swap over.

Still havent determined weather KDX200H springs are the same length as the E2 KDX 90

No they are a different length. Shorter if I remember right. They will fit your 90 KDX forks but you need to make a new spacer.

what is the best stuff to use morie.. and how and where do i measure from sorry dude im new to suspension and wouldnt have a clue

I would imagine that you would just measure the extra length from old spings to suit the shorter springs to compensate. and add a little for preload... PVC pipe? any particular strenght probaly wont need much

Pretty much. You need to measure the interior length of a fully extended fork tube from the bottom to the top of the tube, minus the length of the fork cap. Then measure the length of the springs and subtract it from the fork tube length. The result is how long your spacer needs to be for 0mm preload. Add 5mm preload to the length and start with that for a spacer length. Schedule 40 PVC is what is commonly used.

Hey. Take time to read this spawn

A lot of info on what you need.

http://kdxrider.net/forums/viewtopic.ph ... highlight=

This is getting murky..to me anyway.

You can get any spring spec you need from a number of places...like RaceTech. Well, for relatively recent models. I didn't check it for an 'E' model.

The 'H' springs are generally 470mm. I doubt they are all the same length. Springs are just like that.

To be specific...MY 'H' springs were 470mm.

OK..I did look it up. A '90 KDX uses a 3750 series spring. Stock rate is about .30kg/mm.

So...the first post says '470mm .32'. If yours are 470mm, then they are the same as the 'H' model spring.

Later, 'Are 'H' the same length?'

The answer is definitely YES.

Fluid? You can buy fork fluid from lots of places on the web..from a lot of $$ to a ridiculous amount of $ (like $40 a quart).

Jeremy Wilkey (MX-Tech) has recommended Mobil1 ATF in the past. That is what I've used. I have no complaints. Seal life is fine, works fine. It's around $4 a quart. It's available on-line, too.

Re: couldn't find sched40

They call it something else 'over there' as I recall. Basically it's the thicker of the two commonly available poly-vinyl-chloride (PVC) piping used in water supply plumbing all over the world. It's about 3/16" or so.

BTW..use of the thinner of the two pipe is worthless for any conceivable use..plumbing or otherwise.

I'd measure it up a bit differently. Put your spring in the fork, thread on the cap. Leave out any spacers, washers, etc. you don't have to tighten the jam nut to the cap..just insure the jam not does not prevent the cap from threading all the way on.

Extend the rod. Measure the space between the top of the spring and the bottom of the cap.

Subtract the amount any washers will take up. The resulting figure is the null figure. A spacer of that measure will result in zero preload.

Cut a piece of PVC to suit.

Cut it square. Use a miter box, table saw or some type of guide. A free-saw with a hack or hand saw will unlikely BE square.

Clean up the ends. Put it in.

Don't overlook the spring seats clipped to the bottom of the spring. If they aren't on there when you take the springs out, make sure they aren't still in the bottom of your fork. If they are missing, I'd get some. No, they are not listed as an available part on the BuyKaw site. I don't recall a Kaw PN posted here or there. A fork/shock place may have them.

Hey canyncarvr
cheers for the info dude just from the first post i was assuming thats what size my springs were by the sounds of it your probably right 3750 length and a weight val of .30k i did mean to put 30 in but put 32k instead on the post so they would be different i would say.