KDX250SR fork springs...

kmx125r

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May 23, 2000
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#1
Hey All,

After my first weekend on the track I noticed that my forks were riding pretty low in the stroke even while on the flat. Even standing the bike up straight the forks drop down about 2 inches. Stock springs are supposed to be .35, what would you recommend me to replace them with? I weigh 170#, ride mostly light MX (no BIG stuff, just easy doubles!) and ride trails.

Who is a good source for springs and what am I likely to pay for them. I'm assuming that springs for the US version of the KDX250 will fit my SR model. Anyone have experience with that?

How about oil level with stock valving? Can I use ATF in the forks? What should I look for in fork "sag" in inches? I have the rear set up nicely to 100mm and it works great, but the front is way too soft.

Thanks.
 
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dirt bike dave

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May 3, 2000
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#2
I think I used 0.41 kg/mm when I had mine for trail riding, weight about 180 pounds. When picking fork springs and valving, remember that bike weighs more than most 500 cc 2 strokes. Kawasaki really had a bad set up on the stock forks. Revalving them will make a huge improvement. Mine were VERY plush with the 0.41's in the woods after the forks were revalved.
 
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Oct 31, 1999
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#3
I have a 91 KDX250 US model. It used to ride like a Buick. I unserstand the stock 1991 spring was 0.34(!!) and 0.35 in 1992. I went to 0.40 and it was excellent improvement! Best improvement you can make IMO. I weight 155 and ride in the SoCal area where there are whoops and stuff like that (no MX). I got the spring from "Too Tech" suspension in CA, USA (310)371-3887. I think the part was Race Tech fork spring FRSP395140. 512mmx39OD (maybe 38.6mmOD?). 0.40kg/mm. It may also be available from White Bros. You may need to turn down the plastic spacer slightly so it doesn't rub the inside of the spring.
 

kmx125r

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#4
To Wombat - plastic spacer?

Hi Wombat,

What plastic spacer are you referring to? I had my forks apart about a month ago and don't remember any spacer???

Thanks.
 
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#5
On my bike there is a white plastic spring guide which rides on the push rod inside the spring. Its about 6" long and fluted. The diameter needed to be reduced slightly on miy bike to prevent binding with the spring. It can also be seen in some photos in my 91 shop manual. Its also visible in the little owners manual that came with my bike.

Cya