KDXRIDER.NET

After reading all about the magical KX fork swap, I found a front end off of of 2004 KX125 (thanks krazyinski) and did the swap. I had my first real ride on the forks this past weekend. Trails were mostly 4'-6' wide with volleyball-sized rocks EVERYWHERE. Uphills, downhills, ruts, roots, off-camber switchbacks, etc. There was some single track but it was mostly as previously described. Dry conditions with very little mud.

Unfortunately, I did not adjust any of the fork clickers prior to the ride; they were at their stock mid-point settings for most of the day (my fault).

The good: I can't believe the stuff I went over without falling! I kept thinking "Ah crap, I'm going down this time", but the bike just kept going. No severe handlebar deflection, no problems steering the bike...it just kept tracking wherever I pointed it. I am positive that my old forks would have sent me to the ground repeatedly in those conditions. I only fell once and that was my fault, not the bike's fault.

The bad: That bike absolutely beat me to death! I had arm pump within the first 5 minutes and I felt like I was on a pogo stick! And I wasn't riding fast either (well, I was trying ).

The ugly: I have had trouble just walking ever since I got back from that ride. I am sore in places I didn't know I had.

I did soften the compression & rebound clickers late in the day, and that seemed to be a step in the right direction, but by then I was so beat down that I just wanted to go home.

So, I guess this mod has promise for me once I learn how to dial in the clickers.

Mine are set all the way soft as I think most stock KX conversions are. It's useable but really needs valved correctly. Has a really harsh mid stroke.

Stock late model KX fork valving = arm pump for the average trail rider. Even the good trail rider for that matter. Getting that first 2-6" of travel softer is the key. My buddies 03 YZ250 is unbearably harsh even with the comp clickers all the way out. The comp adjusters (clickers) affect the BV and LSC way more than the MV and HSC anyways.
"Really needs valved correctly" is very ...correct

Thanks guys, the validation is encouraging. I weigh 220# w/o gear and I'm running the stock springs; I realize I'm big for those springs but I figured that could contribute to some softness. Yeah, right...

So, I'm looking at another $200 or so for revalving??? I remember reading about "shim stack" adjustments and so forth...is that the revalving process, or is it something else? Sounds like something I should pay someone for, what with me being clueless and all.

Yep...your shim stack is your valving.....

mid stroke is not so bad after Base valve corection on my 98's. how ever its still there. I run my forks at 13 comp 11-12 rebound. preload and spring rate will cure some problems. I just installed my sub tanks but the rain is keeping me from testing the set up.

Here's what I'd do:

Your forks springs, if stock, should be 42's. For your weight -off road use, you'd only go one size up if you are an experienced rider...you sound like your are not that experienced yet, so I'd say those stock springs are likely OK for you.

Remove the gas tank, tape a 2x4 to the top of the handlebars to protect everything (if you have hand guards remove them), use vice-grips to close off the tranny vent line and flip that bike upside down. If you have access to an air wrench and the allen wrench you can zip those valve stacks right out. Whatever number of largest diameter shims are in place in the shim stack, reduce them by one-third. Put it back together and flip the bike right side up again. Work the forks up and down well to get the fluid level stabilized. Pull the fork caps off and suction out 1/2 inch fluid each side. Put it back together. You now have a resonable starting point for reference. ( I'm assuming the forks were not already modifed for off-road).

Set the rebound clicker to center of available turns. Set the compression clickers to 4 in from full out. Go ride and see if you are now getting enough travel and if forks are more compliant on rocks, square edges etc. Stick some zip ties on each leg about 3 inches above base..that can tell you how much travel you are using. Still not getting enough travel? Remove another quarter inch of fluid. Still too harsh? Remove another 1 or two shims. You get the picture. No need to spend big bucks yet....

OK so I left out a lot of details...but the details are here in this forum...just do some searches. Doing just this, I got my KX 500 forks dialed in very nicely.

kawagumby

great tip

Kawagumby, many thanks for spelling that out. Between your post and the other info from guys like Carvr, I think that even I can handle this.

And you're right, I AM an inexperienced rider, but since I could handle that non-valved too-stiff bucking bronco in the woods, maybe I'm a better rider than I thought? Nah...