Fork Spring Rate

They are .35kg/mm

Make sure you set your rear sag to 95~100mm to compliment the fork springs. I neglected to, and didnt feel the full potential of the heavier springs until I set the rear sag, and played with the preload a bit.

40:

The answer to your question (and likely many others you'll have from time to time) can be had from:

http://www.buykawasaki.com/site/home/

With the entry of model&year, you can see IPBs for your bike along with all the kawi part numbers and in many cases options available (ex: fork springs).

You would see this:
REF#......PART#...............DESCRIPTION
44026A 44026-1575 SPRING-FRONT FORK,K=0.36 2 (OPTION)
44026B 44026-1576 SPRING-FRONT FORK,K=0.37 2 (OPTION)
44026C 44026-1638 SPRING-FRONT FORK,K=0.35 2


IPB=Illustrated Parts Breakdown

If you're headed toward .40s, consider honda XR400 springs. They are hotwound (most aftermarket springs are coldwound). OEM spring length will run 470mm or so, the hondas are around 530. The added length allows you to cut your own preload spacer of a reasonable length as opposed to the 90mm piece-`o-steel that is used in the oem makeup that gives you something like 30mm+ preload.

Can you say, 'B-O-G-U-S!'

......imo and all that.....;)

canyncarvr,

Do you know the spring rates on these stock XR springs? I too am all about the elimination of excessive spacers!

Brandon

I too will be replacing my fork springs during the winter overhaul. What year XR400 springs are recommended? I assume you are referring to stock Honda components as the aftermarket can supply a hot or cold wound spring.

What determines the final length of the spacer?

Thanks,

Gary

A 2000 XR400 has .40 springs. If I recall from earlier searches (there was some confusion posted on this part) there are years close to '00 that are .41.

*****edit*****
Yes, I'm referring to honda springs, NOT aftermarket springs FOR a honda.

What determines the length of spacer is the amount of preload you desire. In my case, I wanted to keep the oem locating washers. The smallest spacer that could be used due to the shape of these washers was about 6mm. This gave me a preload of 9mm. I would have preferred less, but it works fine.

The difference between an aftermarket 470mm long .40 spring (eibach) and the 530mm honda spring was stark! With the former, I could feel every pebble I rode over, with the latter....all that went away.

Which is fine with me!

Thanks. I'll make my order. A 6mm spacer would make more use of the spring than a 90mm.

Gary

RV6:
So you would think.
However, there is argument for the shorter spring...three that I've heard of.
1. Weight

I didn't measure the different springs. Wish I would have. It's not a given that the longer spring has to be heavier. Next time I change my fork oil, I should check.

2. Transfer of motion

There is a time delay from when the bottom of the spring receives a 'signal' (event, bump, whatever) to when that same event is applied to the bike itself. The longer the spring, the longer the delay. This could be argued as a bad thing in a longer spring.

3. 'They' (kawi engineers) must have configured the fork that way for some reason.

No explanation necessary.

Those three ideas came from persons knowledgeable on the subject (suspension). While I can't say I see any credence to any of them..I'm certainly no suspension whiz.

There are a few other users on this forum that have switched to the XR springs (dazza for one) and are happy with them. I tried four different spring sets before choosing the XR springs (at a local tuner's suggestion). There is NO comparison to the XRs from the 'for kdx' aftermarket replacements. It's such an obviously better spring setup I don't know why everyone doesn't use 'em (well...if you need .40kg/mm anyway).

imo and all that.

BTW..use a piece of schedule 40 1" PVC pipe for the spacer. It's a bit tricky cutting such a small piece 'square'. I cut mine a bit long and filed 'em to be square.

Cheers!

Anyone know if the XR springs will work in the E5/6 inverted forks?

I thought they were different. You can run your model through race tech's spring info page to get 'type' and compare it to the '00 XR.

Don't think it's a match.

Is there anyone else on the line who made this change and what are your opinions/results??? Can anyone elaborate on CC's listed short spring arguments??? Is it a given to change the valves while your in there??? Thanks.

Fuzzy,the xr400 springs will not work on E5/E6 .Only on the "conventional" forks.
I back CC.Before I switched to WP forks I used OEM XR400 ,01 model.
By memory the spring rate was 40 but thats what the honda guy said,so who knows?
The Xr springs totally changed the way the bike worked.
I liked it.
I think the longer the spring the better.
More coils that "work" not this half effort metal spacer that does FA.