KDXRIDER.NET

I've got everything I need to swap a set of kx 125 forks onto my 2003 KDX 220. While I have the forks apart for a rebuild, I wanted to ask what springs people run.

If I use racetech's spring rate calculator for a kx 125 and my weight, I assume the math will be wrong due to the different bike weights.

How did you all go about determining a spring rate?

Thanks.

EDIT - I am planning to use 2001 KX 125 forks.

I resprung my KDX earlier this year with 0.44kg springs and like the ride quality. I assume I should continue to use that rate, but with a KX spring...

Please correct me if I'm wrong.

When doing a fork swap onto a KDX. see what it says about the KDX, as you are riding a KX, not a KDX. The weight of the forks / wheel / brakes / etc. will not change too much.

I think he means, do the calculator with the riding style you are doing and use the KX125 for the bike.
I'm almost positive it would come out the same or real close if you put both bikes in and the same riding style.
In other words, it's more about your riding style and weight than it is the bike that you are riding. Generally a KX fork needs to be lowered for use on the kdx, so if you do this (even if it's just shoving them up in the tree) and they have an option for a lowering kit, make sure that info is correct within the calculator.

No. See which springs you need for a KDX. A KX125 (last year) is 208 wet, so about 25 pounds less than a KDX200/220R from 1989 on, so...about .02 difference in spring rate.

If you are going to lower the forks, look at Yamaha springs, as they are shorter. Don't preload the **** out of some Kawasaki springs inside lowered forks.

Using the RT Calculator:
If I plug in a 2003 KDX: .44kg springs
If I plug in a 2001 KX: 0.42kg spring

I talked to Race Tech today. They recommended that I keep the same spring rate that I had in the KDX forks, which makes sense. The bike weight is added to the rider weight to get an overall sprung weight.

I'm going with the kawasaki spring and just sliding the tubes up in the clamps. I have plenty of room to bring them up 3/4 of an inch or so with my risers, this shouldn't impact my preload.

Jason wrote:No. See which springs you need for a KDX. A KX125 (last year) is 208 wet, so about 25 pounds less than a KDX200/220R from 1989 on, so...about .02 difference in spring rate.

If you are going to lower the forks, look at Yamaha springs, as they are shorter. Don't preload the **** out of some Kawasaki springs inside lowered forks.

Which Yamaha fork springs would you reccomend? Just any that are the correct mm in diameter ? ie: I have a set of 98 KX 125 forks. 46mm, would I look for 46mm Yamaha ?

I'm looking forward to doing this KX fork swap...

Currently have klx300 forks on my 220..

measure the springs, not the tubes