Race tech shock spring-Crap!!!

Hi all

can someone please enlighten me as to what the hell is going on.

I have a kxf 250 07, the racetech spring calculator said for my weight (139lb without gear, riding motocross with std tank) i need a 4.8 spring.

I have it installed but cannot get the sag i need :thumbsup: :thumbsup: .

All the readings have come from slowly pushing, slowly pulling then taking the average. the difference between the two was never more than 10 mm so i presume the linkage is ok, but will regrease today anyway.

Ok min and max pre-load for my bike is :-122.1 ∼ 131.6 mm, Std: 123.5 mm,

the best i can get is preload 131.6 mm, race sag 94mm, static sag 33mm.

First day back on the track and i nearly killed myself, the thing was real springy,swapping and bucking me over the bars!! :thumbsup: .

This really sucks as i live in france and had to wait 2 weeks for the spring

can someone please tell me if its the spring thats crap, my bike or me.

Something else (please comment), don`t know if this means anything when i push on the seat of other bikes the seat returns resonably quick, but mine (with previous and new spring) returns very slow :thumbsup: .

Thanks in advance Lee

You really should grease your linkage/swingarm before coming to any conclusions.

are there some numbers stamped on the spring? maybe you get the wrong one (stiffer than 4.8)

Something else (please comment), don`t know if this means anything when i push on the seat of other bikes the seat returns resonably quick, but mine (with previous and new spring) returns very slow :thumbsup: .

what is your rebound setting? (it's also possible the spring cannot expand enough when the rebound is completely closed)

sounds like your rebound needs adjusting.. also the spring may need a few rides to settle into postion.. i wouldnt acuse the spring right away. everything needs a break in period. i would give it a good 2 rides.. the try to adjust sag.. give it 1 more ride then if your not happy then something might be wrong.

i would ignore the preload limits, adjust to 100mm with approx 36mm free sag and i bet it will be ok.

have just checked all bearings and they are sweet (bike doesn`t have many hours).

checked the numbers on the spring and they correspond to numbers on box 4.8.

spring should have settled it`s got 6 hard hours on it.

clickers are 12 cd and 8 rd.

also just checked shock shaft, with presure it compresses smoothly and slowly returns to full extent.

Quote""

i would ignore the preload limits, adjust to 100mm with approx 36mm free sag and i bet it will be ok.

MOG shouldn`t it fall within recommended preload limits (I thought that might be why i was getting a wild ride, to much pre-load isn`t good is it??), and isn`t 36mm free sag to much

excuse me for accusing but these readings are very close the previous stock spring 5.1

thanks lee

Hi Lee, but you have too much preload not too little, less preload is more sag, with lighter riders you have to verge on the higher free sag range as you wont get it to handle right with "perfect" sag numbers, the weight of a 4 stroke is too much, you will get a lot of chassis movement with a 4.5 rear spring, your numbers for the spring are close probably as the 2 springs are close in weight, your std one could well measure near a 5.0.

Ok thanks MOG will give it a try, reduce pre-load to get 100mm race sag and i won`t worry to much about free sag. i`ll post back with the free sag it gives

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