SX springs in my '99 EXC

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#1
I found a good deal on a set of 4.2Nm springs, so I bought them for my '99 300EXC, stockers are 4.0 I believe. Anyway, I plan on trying them out this weekend. I am assuming that I will be able to back off my compression at least 4-5 clicks and maybe slow down the rebound a click or two. Anyone made this change to SX springs in the EXC? And what did you do with your adjustments?
 

Strick

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#2
Montana what is your height & wieght? Let me know how they perform. I am interested in doing the same to my 300.

As far as advice, I would just get the bike warmed up, ride terrain that you ride mostly, have a screw driver handy, and move each clicker (separately) 2 clicks at a time in each direction until you get the feel you want.

Let me know how it works out.
 
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#3
I thought you might be the first reply Strick :D

I am 5'-9" and weigh 185lbs. dressed, probably close to 200 lbs. in my dirt bike gear. I don't really have any complaints about my stock forks, but I was speaking with some riders last weekend who had gone to stiffer springs in their KTMs with good results. The predominate theory being that a stiffer spring kept the fork in the lighter initial valving on the trail trash, and provided for less bottoming on g-outs, jumps etc.

I always keep the screw driver handy in my cross bar pad for those necessary adjustments, susp. and air screw. My riding buddies think I mess with my bike to much, but I like it just so :)

I will report back Tuesday with my findings.
 

TexKDX

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#4
My '99 300 had 4.2s in it when I got it used and I went back to 4.0s per Factory Connection's recommendation. They actually measured out at 4.1 BTW.

I weigh 170 nekked, competitive B class enduro rider. 15 pounds may make the difference, maybe not. As far as the spring/dampening concept the guys are telling you, that is a new one to me. I suggest you talk to a WP service center like White Bros's suspension dept before making the change. They are pretty good with WP stuff.
 

Shaw520

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#5
Originally posted by Montana300
I

The predominate theory being that a stiffer spring kept the fork in the lighter initial valving on the trail trash, and provided for less bottoming on g-outs, jumps etc.
I found this to be true, more so with bigger guys. If you are heavy enough to compress the suspension past race sag specs, (95mm) or 3.5", (indicated by checking race sag), then you are most likely riding in the more harsh section of the stroke, which will result in the loss of plushness found at the top of the stroke. Myself, 6'-1" 280#s, agressive B class, was recomended to use .50's in the front and 9.6 in the rear, which I initially thought would be waaaaay too stiff. To my surprise, these rates work extremly well for my weight, and even felt more plush on trail junk, with greater bottoming resistance. I found I could take bigger whoops more agressively, better landings on jumps, and still plenty plush for woods junk. The front end seems to bite better with alot less wash. Try going stiffer, very important to get race sag @ 95mm. Good Luck
Montana, You're pushing 200#s, If you are an agressive rider, you will definatly benefit from a "stiffer than stock" spring rate.
 
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TexKDX

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#6
You can also try a little more preload on the front to keep you up in the stroke. Check the current shim, then cut a new one out of PVC pipe 1/4" to 1/2" longer. This will raise you up in the stroke without effecting the spring rate. Shaw, are you talking 3.5" in the front??
 
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#7
I got three days testing with the SX springs in my '99EXC. The riding consisted of everything from heavenly 4/5th gear single track to 1/2nd gear rocky areas. I used the stock 10cm [I think] preload spacers.

For any trail where I could use 2nd gear and higher, I really liked the stiffer springs. The slow going rocky sections were rougher, but there was very little deflection. It's almost as though I could feel the rocks more, but they didn't disrupt the bike. While experimenting with the clickers, I ended the weekend full soft on compression and three from all the way in on the rebound side. The compression changes really didn't seem to make as much difference as with my stock springs.

The balance of the bike is changed, so I had to adapt to that, plus I decreased the rebound damping in the rear one click to compliment the stiffer front end, which I didn't want to have to do. If I was really going to get serious about making changes to my suspension [the stock stuff is fine by me, I just got the fork springs cheap, so I decided to experiment], I would get the stiffer shock spring also.

For now I am going to leave the 4.2s in and ride a few different areas before making further conclusions. Actually, I want to like these stiffer springs for all conditions because I really like the confidence the stiffer springs provide on fast downhills or G-outs etc.

So, the 4.2s aren't the perfect setup for me, but I may stick with them despite the tradeoff's. Maybe I will try less preload, see if that softens them just a bit.
 
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#8
Montana300

FWIW, if the .42s are a little too stiff you might consider Eibach .41s for the '99 available through White Bros for a reasonable $80.

------------------------------------------------ยป

Bret

1999 KTM 380SX
1987 Husqvarna 430CR
 

DanS

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#9
Some guys run different springs in each leg to get a feel that is between the two spring weights. If you run the 4.0 in one fork and the 4.2 in the other it should give you the feel of having 4.1's in both legs.
 
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#10
I thought I had read about running two different springs, and even considered just installing one of my 4.2s. I am assuming that there are no long term effects of running two different rates, such as undue stress on the forks?
 

DanS

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#11
I'm not aware of any problems. On our '99 300EXC's the left leg is compression and the right is rebound. There is as much if not more stress on this setup compared to slightly different spring weights in each leg. I know at least two tuners that do this and say it works well if you need a spring weight that is between what's availible.
 
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TexKDX

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#12
Some trials bikes run NO SPRING in one side; just the dampening mechanism in one side and the spring in the other. FWIW.