USD guys - How many haven't revalved???

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2001kdx
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USD guys - How many haven't revalved???

Post by 2001kdx »

Have any of you guys who did the swap on the MX valving still? I'd like to know, How do you stand it??? My RM250 has an MX revalve and I have it clicked full soft, reb. and comp, and it's extremely harsh! I don't have the cash for a full revalve right now and I'm not a full-on woods rider (I like going to the track) but for general woods riding, we're talking northeast stuff here, mud roots and ruts, very little rocks - It's too damn stiff.

i mean I can deal with the 2.1 gallon tank, small flywheel mass, and tall gearing, but I NEED the suspension plusher! I rode the 'ol KDX the other day and I was mezmorized.

What I might do, is once I get some cash gathered up, I'll snag an extra set of forks & shock that'll fit on ebay, then send 'em out to get revalved and sprung for woods riding. But.. until then I'll have to ride it out. The good news is It takes huge monster doubles at the track for breakfast :supz:
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Jeb
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Post by Jeb »

I've still got the stock valving in the YZ USDs I put on earlier this year but that will change soon - I'm gonna tear down the forks this fall, revalve, and change things up with the rebound/active config.

One thing I did when I rebuilt my forks that you may consider: remove some of the bigger shims in the base valve (do a search, there's plenty of threads on this). A typical shim stack for MX USDs (at least to my knowledge which is part heresay) contains a series of a bunch of the bigger shims - like 10 - before the stack starts necking down with smaller and smaller shims. As recommended by others, I removed 7 of these bigger shims in each valve. These bigger shims were located directly below the valve and with 3 compared to 10 you have more flex to allow suspension oil to flow by more easily. Given the ease with which this is done, it's probably worth a shot. At best, though, this mod will likely fall short of being perfect for the woods (that's my experience and is why I'm revalving this fall).

I am assuming that Showas are similar to KYBs in this regard. Also, you might lose some bottoming resistance on those monster doubles (I wouldn't know - I'm not a monster-double kind-of-guy!!)
Last edited by Jeb on 03:34 pm Sep 09 2007, edited 1 time in total.
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kawagumby
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Post by kawagumby »

Check and see what the spring rates for your RM are. Both the springs and damping resist movement, albeit in a different manner. Back in the 80's,manufacturers used soft springs and harsh valving on the production bikes, since then the trend is otherwise.
Some generalizations from my experience;
I've found that if you have adequately revalved the forks and they still lack compliance in the intitial half of travel, you probably need a softer spring. Stock MX shock valving is usually OK for woods when used with a softer spring.
If you are 160 lbs or less the stock MX springs are very likely too stiff for off-road, and are actually more than what is needed for average skill outdoor type mx work too, IMO. On most non-prepped dry tracks, more compliant suspension = better braking, control and acceleration.

I revalved my KX MX forks on the KDX by simply removing more than half of the large compression shims AND (very important) dropping the oil level to where it would just occasionally bottom on the worst of hits (the only time they bottomed was during that suspension testing). My forks are stellar - I love them, and they are using 40 kg/... fork springs. I weigh 165.

PS I recommend flipping the bike upside down and spinning the compression valve out with an air wrench. Fast and easy.
1994 KDX200, Beta 200rr, yz125, yz250, kx100 modded for adult, gasgas contact 250.
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thebleakness
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Post by thebleakness »

My suspension 'expert' tells me that if your not bottoming out at least once on a course then it needs reworking. Bottoming out shows you that you are using your full suspension travel and makes sure everything inside is working.

This is the problem with my 450. I can't and even when I flat land a big jump compress those things down. I have about 2 inches left of travel that are wasted. And this is on an MX track keep in mind, imagine what it's like on rocks....

So I'm going to have mine professionally done. I think I am going to go with Johhny of Twisted Wrenches because he's been Destrys mechanic for a long time now and has done all his suspension work. I think he would know what a good set-up would for WORCS stuff would be.
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2001kdx
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Post by 2001kdx »

If I were to ride trails all day and never catch air... I'd have at least three inches of unused suspension travel in the fork, clicked full soft. The shock on the other hand... is adequate. It doesn't bother me nearly as much.
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thebleakness
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Post by thebleakness »

And on the track, do you bottom out? You might just need some lighter springs...
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Post by KarlP »

'95 KX125 forks on the '02 KDX, not revalved but I had them cleaned out and rebuilt by a decent mechanic (I believe)
He used 5 wght oil at the lowest level in the spec. I think they are just right. I'm running rebound at 8 clicks out and compression between 17 and 21 clicks out, depending on terrain
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Post by MXOldtimer »

03 125 forks. I rebuilt and used Redline light oil (5wt) with stock valving, my clickers are almost full soft. They're a little harsh poop'n along but once up to speed they're working better than I expected. I use a zipty to find out I'm using all but the last inch & a half under speed so they're not far off. Will probably drop one spring wt. later and see how that works out.



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