Fork Springs; Aftermarket vs. XR400

[40]

I'm planning to purchase some .40 fork springs for my KDX. I have seen several posts suggesting stock Honda XR400 springs. I'm aware that they are a different length than stock (or any aftermarket spring for the KDX). So I'm deciding between aftermarket .40's and factory Honda .40's. How does their performance differ?

 

[canyncarvr]

I use 'em. Dazza used 'em (before his fork swap)....among some others. Supposing you've already read what we have to say, you're asking something else?

Please ask specifically if you have something in mind?

 

[KDXFreestyle]

:uh:

 

[40]

canyncarvr,
I have read most of what has been posted before. I'm aware of the different setup required to use the XR400 springs. I don't understand how the XR springs perform differently than an aftermarket set with the same spring rate. So why use them??

 

[Kawadougie]

I use XR-400 springs because the spring rate is heavier and works better for my 185 pound butt. The difference is that the XR springs are longer and use a 10mm spacer v/s the stock long spacer. The only advantage over an aftermarket set is price. Most XR-400 owners toss the stock springs in favor of heavier ones and they are just the right size for most KDX riders. You can buy them very cheaply. I paid $20 for mine. :yeehaw:

 

[GreenPeace]

Im convinced its a good move.
What specs must I ask for at the local dealer? ( lenght and kg )
Weight = 170lb.
KDX 200 '97

The only way I solved the headshake was to extend the front spacer with 20mm. ( standard springs ). That turned small pebbles into rocks.

 

[canyncarvr]

40:
A couple of reasons they are 'different' than aftermarket springs of the same rate.

1. Length. 470mm is the oem length, the 400 springs are 530mm or so. The longer a spring is, the more linear movement it will take with a smaller change in rate. Exaggerate to make the point. Take a 3' long spring rated at 20lb/in. and a 3" long spring that is rated at 20lb/in. The shorter spring is going to give you that rate for a much shorter distance of compression than the 3' will.

2. OEM springs are hotwound, aftermarket springs generally coldwound. A hotwound spring will in most instances keep its length longer than a coldwound spring will. That's a good thing if you want your springs to keep their length inbetween oil changes.

3. Cuz they are superior.

I've used .40 aftermarket springs (470mm) and the .40 honda springs. The difference was considerable. A much softer ride on the top of the spring, a more smooth, linear compression.

While I've heard argument to the contrary, I have heard no reasonable argument why a 3.5" steel tube in a fork is better than using that 3.5" for spring length. 'The kawi engineers must've used a 470mm length for some reason' means nothing to me.

In the end, I imagine it amounts to what suits you. The honda springs were recommended by a local suspension tuner. I tried a set due to aftermarket (brand new) spring failure..one of 'em collapsed. The difference was obvious, apparent and a hands down choice.

Whether they suit anyone else is certainly up to the their discrimination.