Stock KDX Forks

[Lew]

I desperately need to put stiffer springs in both mine and my sons kdx's, they feel like a rocking horse when you touch the front brake alone. I am planning on doing this in the next month or so. I have a few questions.

1) Why doesn't the kdx have inverted forks? It seems to be the only larger bike out there that does not. (ktm exc, yamaha wr)

2) Can inverted forks be applied to the kdx? Expected price?

3) If so, are the inverted forks worth it?

Thanks for the help
Lew

 

[kaw Bill]

I think most people just upgrade the valving in the stock forks. I have racetech valves in my kdx forks and it's a definate improvment. If I was going to do it all over again I think I would send them to MX tech and have them serviced and revalved. People on this site report excellent results with MX Tech.

kaw Bill

 

[andrew]

g'day Lew!

Although I have no personal experience with inverted forks, or USD's, I am led to believe that conventional forks are now considered to be 'better' than USD's for enduro/trail applications. I'm not too sure of the technical reasons for that, but you may have noticed some brands of bike that previously sported USD's are now back to conventionals. KDX was one of these, i think it was the '93 that had USD's, then later models went back to conventional.
I do know that my conventional forks don't blow fork seals as often as my mates WR200 with USD's...

Anyway, back to your question, it would be costly I would think, to put USD's on your bikes. you would need new upper & lower triple clamps for a start, and then your head stem bearings could end up being the wrong size; you'd need new brake calipers etc etc...

Far easierto put in an aftermarket set of springs, and perhaps some revalving with a reputable suspension specialist. I can recommend XR400 springs of a suitable rate for your weight, as that is what I have put in mine...

Anyway, hope this helps you a bit,

Cheers

 

[Simon Fuller]

There as been some previous posts about putting kx125 usd's on the kdx. I think Sage has performed this mod.

It seems pretty costly and you could probably stick with the std forks and spend the money on revalves etc to acheive a similar result (except the huge underhang!:mad: )

 

[Robcolo]

USD FORKS & FREE Heavier Springs

USD forks were designed for one thing - rigidity. "Reguar" forks were flexing too much from the big air landings encountered in supercross. Unfortunately, this rigidity is a negative for all but the fastest trail riders. You can easily turn any spring into a heavier one by simply cutting off 1 or more coils. There's a simple formula [which I can't find right now] for computing the amount to remove. [MX-tech would know it] I use an air grinder to quickly cut through the hardened steel, then heat back about 1/3 turn with a torch and bend the fresh cut end down to touch the next coil [this forms a finished end like you just cut off] Yes, you do lose just a bit of spring length in the process but I've also built a spring stretcher to regain any lost length. It's also great for restoring a set of "sacked out" springs.

 

[DVO]

Andrew:
You said you can recommend a suitable weight XR400 spring. I've been trying to find out if honda makes a different one than stock and had no luck. Even the local dealer couldn't help me.
I want specifically OEM parts 'cause they are hot-wound and get much better reviews than after-market. I'm about 180-185lbs without equipment and from what I've seen, I need a 0.42 kg/mm spring. Does Honda make these? I believe the stock ones are 0.40kg/mm.
Thanks for any help you can give me. A part # would be fantastic Thanx again, DVO

 

[andrew]

DVO...

Sorry mate, you mis-understood the context of what I was saying. My fault, I had to go back and read my own post before I realised that the way I wrote it was misleading.

What I was trying to say was that I do recommend XR400 springs (whether OEM or aftermarket) of whatever weight is suitable for you...

I used an aftermarket set by Eibach and have found them to be very good. I have no idea about Honda OEM parts. I imagine they would make a .42 spring, and I don't understand why the local dealer can't help. Try one of the big honda dealers on the internet - you should be able to find something. Canyncarvr seems to know a fair bit about the Honda springs so perhaps a PM is in order.

Again, sorry for the confusion,

cheers,