'03 kx125 setup

[Matt_H]

I was wondering if anyone has come up with some good setup using the stock setup(springs valves). I'm on the heavy side for a 125 at 195 with gear, and was wondering if anyone around my weight has done anything with the suspension?. thanks

 

[marcusgunby]

What do you dislike on the suspension.

 

[dbrace]

The correct springs for your weight is the first step

 

[Matt_H]

Well for starters then what would be the proper spring rate for a 195lb person?

 

[marcusgunby]

Its tricky as different web sites say different things.I use www.mx-tech.com and goto spring rate generator.One tip on the 03 KX125 is the forks have too little rebound as std and pop up badly off jumps etc.I put 4 more clicks of rebound on the forks.

 

[Matt_H]

Your stock fork spring rate is.....42kg/mm
Your stock shock spring rate is....4.9kg/mm
Your recommended shock spring rate is....4.78kg/mm
Your recommended fork spring rate is....0.4329kg/mm

Am I understanding this correctly? I'm suppose to get a lighter shock spring but beef up the forks? Could I get away with just putting heaveir fork springs in?.

 

[marcusgunby]

Ive heard the 03KX125 fork springs are testing at 0.43kg/mm , to be honest you are close enough that i wouldnt bother with different springs.So we come back around to the original question , is there any perticular aspect of the suspension you are concerned with.

 

[holeshot]

I called a couple of Kawi dealers and asked what the stock fork spring rate is (it isn't listed in the owner's manual or the shop manual) - one said it was .40 and the other said .43. Springs rated at .40 and .42 are listed as optional in the owner's manual, so I'd guess that the stock springs are .41, since that's the only gap in optional spring selection. But it's only a guess :confused: .


I'll try the rebound at about about 8 or 9 clicks - thanks for the tip.

 

[marcusgunby]

Im sure my manual says its 0.42, or the kwak website says it is.

 

[Rcannon]

Marcus, is there a tolerance in the springs? Have you ever seen new ones that were not within spec?

Most industrial springs I have seen ahve a certain percent of deviation. At even 5% this would change the motorcycle quite a bit.

 

[marcusgunby]

yes i believe it is 5% on springs.

 

[steve125]

Pete at HDR tested my std. rear shock spring for the 03kx125 and came up with 4.83. Kawie says it's a 4.9 rear and .42 front, the only way to be sure is to have it tested. Race Tech tested the std. springs also and came up with 4.8 and .43.

 

[Matt_H]

I haven't put much time on it but it just seems to react slowly(forks) in rolling rymthem sections. Almost like once it compresses its slow to react and once you hit the 2nd its like its still reacting from the first hit. Hope this makes sense.

 

[marcusgunby]

It sounds like your forks are packing-try reducing the rebound damping, top adjuster (anti-clockwise) 2 clicks at a time until it improves.Also try increasing compression damping a little(bottom of forks clockwise) 2 clicks at a time.Report back to us if things improve. Also jer has a full tuning guide on www.mx-tech.com

 

[Matt_H]

Well worked on it and it got a little better but not much. I talked to the shop thats sponsering me and they took it apart and said that the oil in the forks was more like syrup and they've never seen anything like it along with a small washer in the one fork. So they got it back together free of charge. I haven't riden it yet but was told by the owner that its light years better. but not to worry any of the other new kx owners They said out of about 50 bikes they've sold this year mine was the first with this problem.

 

[marcusgunby]

The std oil does turn nasty after a few rides.

 

[dbrace]

The std kyb oil allways looks like that. Almost stringy.

 

[marcusgunby]

I notice better suspension action from just getting rid of the std oil.Not a big difference but it does help.

 

[dbrace]

Matt the first step in setting up suspension is setting your shock race sag. After u have done this (100mm) u should notice that the rear of the bike has no free sag ie is topped out . This is because for your weight u have had to put too much preload on the spring to get your 100mm. You need to have between 18- 30mm free sag. If your bike has a 4.83kg spring u will need get a 5.2kg shock spring in order to get your race sag and free sag correct.

 

[Jeff Howe]

I don't know what that oil is but it is without doubt the worst crap in existence. Anyone with new KYB forks should dump that garbage immediately. If that is KYB 01 then $25/qt is the biggest ripoff in this industry.

 

[Matt_H]

i'll try to keep everything in mind which I have learned in this as I might go and trade the 125 for a 250 as its cheap and better suited for my weight.