UPDATING KX500 SUSPENSION.

[moto939]

I had a new set of suspension from an '09 450, so the spring didn't really cost me anything (or that's what I like to tell myself), but take off springs can be found on the forums(TT or vital) for around $100-150 if you post a wanted add. Sometimes on ebay a complete shock with the spring can be had for cheap.

'06-09 450s ran a 5.5kg spring. LE models had the red spring, otherwise the rest were unpainted like this...



'06 and up 250fs 250s and 125s also ran the Ti springs ranging 5.3 down to about 4.7 ish. So a variety of spring rates are out there, but I find the 5.5 to be the sweet spot on 250s for my weight.


I'm down for a Guru link if there isn't too may hoops to jump thru to get one. Have an ETA?

[Sandblaster]

Contact Alex Ward at Crazy Al's Racing for the link arms..
208-249-7152

I'm on eBay looking for a spring

[moto939]

Two things to keep in mind....

First, the easiest way to verify the spring rate is by the color code on the bottom of the spring. 5.5 is pink 5.3 is yellow Don't know the rest, but it's a KYB thing whether steel or ti and you'll want to verify it before laying out the cash.

Second, you'll notice a couple plastic spring seats on the ends of the spring. These are a wear item, so make sure they are in good shape and have a spare set in your tool box ( # 1C3-22565-00-00). As they break down (and fall out eventually) you'll start chasing your tail with excess sag. Keep em fresh and the spring will stay consistent.

You can just see the paint dot in this pic.






I have to pick your brain about the 38mm air striker on a 500, but I'll start a different thread when I get a chance.

[Sandblaster]

Excellent info on the springs and the plastic seats..
I had no idea on the plastic seats.
I need a 6.1
None on eBay at the moment but I will keep an eye out...

On the 38mm Air striker... it's good for 1 hp to the rear wheel on a totally stock K5

[moto939]

5.5 is as heavy as you'll find in a Yamaha Ti spring.....you may have to search for a RCS spring.

[Sandblaster]

Or... I'll have to go on a huge diet..... Probably not

[Markee757]

Sadly some of this is inaccurate. Everyone i sent a message to on ebay regarding the top clamp bore has been 54mm for the later model 250f clamps.

I have a early model 11' KX450 set I just pressed out the steering stem, pressed in the 500 stem. Bored top clamp and bushing for top clamp and old stem. Got tired of looking for a bolt up setup...

[Sandblaster]

Cool.
The one thing we are all about on this site is having the most accurate information we can get.

I'm curious though... On the 250f's were the clamps measured or the actual fork tube diameter?
Everything I have measured and documented was measured at the fork tube, not the clamp.
I can't speak for anyone else..
And, specifically, what years were measured and verified?

Here is the measurements off my 07 KX250F forks
UPPER 52.82MM
LOWER 58.35MM

20171020_134509.jpg (185.06 KiB) Viewed 8642 times

20171020_134524.jpg (236.78 KiB) Viewed 8642 times

I also have a set of 2011 KX450F forks in my hands right now.
UPPER 53.8
LOWER 59.1

Here is the measurements off my 01 KX500
UPPER 53.8MM
LOWER 58.9MM

[Sandblaster]

To verify year range for fitment I went to Pro Circuits website.
Note the interchange info on the triples.
Fits The Following Bikes:

Kawasaki KX250F 2006-2012
https://www.procircuit.com/triple-clamp ... 06-12.html

Then I looked at their 450F clamps
Fits: KX450F '06-12
https://www.procircuit.com/kawasaki-triple-clamps.html

So I'm relatively sure that my info is correct.
But please tell me what is incorrect and I'll be happy to research it.

I'm glad that you posted the info on the stem.
I suspected that they might press in and out on both setups but I've never tried it.

[Markee757]

Hey guys, great site.

Just some info...SSS forks and clamps

All have 59mm lower clamping surface

'06-'09 450f 56mm top

'10- current 450f 54mm top

'06-'12 250f 56mm top

'13-current 250f 54mm top

two strokes 56mm top

Hope this helps anyone planning a fork swap.

I'm installing new '09 450f forks on a '01 500. Needed to machine out the stock KX top clamp to 56mm to fit these forks.

I'll post some pics when I figure it out.

I meant to quote this. Sorry about that.

I was in search for a 59mm bottom and 56mm top. I too am putting KYB SSS on my K5. Everyone on ebay that measured clamps in the range of the 56mm tops all responded back with "54mm". Figured it wasn't a fluke when 6 people had the same response with clamps in the 06-12 250F range. But maybe they didn't know what they had.

In response to the fork stem. My 92 stem was .006 smaller than the 2011 450 clamps. I fixed this by putting a small knurl on the press area only. This actually increased the diameter by .013. Leaving me with a .007 interference fit. I know the working surface has been decreased in the fit, but we will be ok. I heated the clamp. Cooled the stem in CO2 for 6 hours. Light coat of epoxy on the clamp, dropped the stem in with the help of a 100ton press. There to stay.

Made a bushing/washer for the top clamp to make up the difference, wasn't much! I'd upload photos but apparently they are to big.

https://photos.app.goo.gl/swns4Ebwr2mNHIeW2

https://photos.app.goo.gl/DU5XuwRl11C9RtL53

If those links work, you will see the brakes that are going on this bad boy.