Fork Srings XR400 or KDX ?

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magaffer
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Fork Srings XR400 or KDX ?

Post by magaffer »

I am in the process of ordering fork springs (03 KDX200).
What I would like to know is if I should order KDX or XR springs ? I have read that there are advantages to the extra length of the XR's ? If it is the KDX's, then Race Tech or FRP ? If XR what year ?

Thanks.
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canyncarvr
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Post by canyncarvr »

The advantages you have likely read about are only opinions of some, the uninformed, those only recently inebriated to biking (har har)...probably ME.

The first thing to consider is the proper spring rate for your weight, riding environs and style. For the same person the spring rates will be different between single track woods and open desert type riding.

Once you know the rate, choose the type you want. If you order springs FOR the KDX, they will be in the vicinity of 470mm in length. The stock preload spacer is about 90mm long and provides about 35mm of preload. That spacer is a piece of steel. If you want to fill your fork tube up with steel spacer, be my guest. Seems reasonable to me that the fork tube should have SPRING in it.

That's where the XR spring idea comes in. They generally run 520mm, so more spring, less spacer.

The advantage of getting springs actually FROM an XR as opposed to getting springs FOR and XR (from mx-tech, race-tech, eibach or anyone/place else) is that the Honda springs are hotwound as opposed to cold wound. That's probably a matter of NO matter to most. I like the idea of the former vs: the latter, so I used actual Honda springs. The packages had red wings on 'em!

Such springs are somewhat limited in choice obviously..you're looking only at what springs came in the XRs in the first place. If you're 275# and looking for a .48 spring, you're going to have to go aftermarket (a spring made by someone other than Honda FOR an XR).

I used to have a short listing of what rate spring fit into what XR..but it's disappeared somewhere..maybe in the last system crash (mine). They range from .38s to .42s or so..in late '90 early 20' 400's/600's. Any stock spring rate can be checked on the race-tech site.

What rate are you after?
Last edited by canyncarvr on 02:15 pm Jun 22 2006, edited 1 time in total.

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Post by Indawoods »

Xr600 93-00 : .41
Xr600 85-92 : .42
Xr650L 93-02: .44
Xr400 00-02 : .40
Xr400 96-99 : .38

It’s the 1996-99 0.38kg/mm XR400 springs that are interchangeable and commonly used in 1995 to 2005 KDX200/220s

The stock 1995 to 2005 KDX 200/220's springs are commonly used to replace the 1989 to 1992 KDX springs, they are a good fit and give much more support in these models.

The Stock KDX spring rate depends on the year of the KDX. The 89-92 KDX's had a .29 spring rate stock. The 95-04 KDX's have a .35 spring rate.

If you have the older KDX200s like the 93-94s with the 41mm forks, you may be able to use the springs from the Xr250s. Same diameter forks.

Xr250 96-02 : .35
Xr250 90-94 : .40
Xr250 86-89 : .38



*I make no guarantees as to fit...
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magaffer
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Post by magaffer »

Thanks for the info.

Seeing as I am 6'2" 250#, thought no matter what spring it would have to be aftermarket, somewhere between .44-.48? .
As far as riding preference/type I enjoy tighter trails with the occasional hill climb, however that is not available locally so.. it is a wide range of single to doubletrack with a few laps of mx, basically any thing to get my ridding fix.
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Post by canyncarvr »

The RaceTech site recommends .45kg/mm for the KDX with 215# of rider...that's an enduro/single track rec.

If you want the longer springs you could just call and ask them about it. I'm sure they could come up with a 36mm diameter spring that was 520mm long in a .44 (or so) flavor.

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Post by grump99 »

Hi there, I would agree with canyn about hot wound springs being better, mine have not shrunk at all after several hundred miles. You might consider the shim stack mod too, it helps a great deal. Good luck!
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Post by canyncarvr »

Hey Grump! Thanks for the input. I recall you to be the latest (and best) write up on the OEM shim stack change.

Think it would be of any use for 250# of 6'2" rider?

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Post by grump99 »

I think the shim stack mod would help any weight rider with stock valving. For me, the spring and shim changes made 100% improvement over stock. It really takes away the high speed harshness and prevents washing out in bumpy turns and nose-diving on downhill braking.

I'm not sure how a heavier rider would factor in though. With a heavier rider, fork flex may be much more noticeable. A set of KX forks may benefit a heavier rider more than an average weight person. Just some thoughts.

Keep in mind ive never tried gold valves or inverted forks so I may not know what i'm missing. Also keep in mind my last 2 bikes were a '78 CT90 and a '74 TS185, so a stock KDX was like an F-15 to me :supz: . On a budget the shim mod was nice, but i'm going to splurge on some KX forks first chance I get. :mrgreen:
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Post by canyncarvr »

re: 'so I may not know what i'm missing..'

I can guarantee that.

I'd read the 'fork flex' comments...pretty much p-shawd that idea as someone looking for something to worry about. The KDX forks aren't exactly puny! My 700SC forks are considerably smaller. No, it's not a dirtbike, but considering the weight and the speeds involved..how do those forks hold the bike on the road?

I was interested in the KX forks from the standpoint of getting rid of the underhang. That engineering gem got me into trouble on a regular basis.

OK. Underhang is gone and I appreciate that fact almost every ride. The improvement in handling over the KDX forks is nothing short of amazing. It doesn't have to be a very expensive swap if you do some decent shopping.

The difference is huge. That translates into a much more enjoyable ride and that's my focus, my goal...to have a bike that works as well as it can..as it should. That translates into more fun!

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