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Fork Height on KDX250?
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Posted by: jmutiger---------------------
Where do you guys run your forks in relation to the upper triple clamps? Currently mine is at full height (level with triple clamp, no blue showing).. Does anyone drop the forks to increase responsiveness? If so, how much can you drop before bottoming the tire on the fender becomes an issue?
Jon!
Posted by: dirt bike dave---------------------
I always ran mine with 3/8" of blue showing; no tire interference problems.
The stock fork springs and valving are way off for most riders - if you haven't resprung and revalved, you will really like the bike much better after the forks are fixed. I also ran no pre-load on the fork springs to help the front dive down for better cornering.
Posted by: jmutiger---------------------
Any Specifics to the revalve required to make it a more woods friendly bike? I found it to be a very good MX feeling setup.. So it's probably way too stiff for Woods.
So if I am to revalve, do you know the recommended stack thicknesses?
What about the rear, go softer too?
Thanks,
Jon!
Posted by: dirt bike dave---------------------
On the front, the bike has way too much high speed compression damping (when the fork has to move rapidly, like on a sharp rock). Kawasaki has done the same thing on other KDX's, and they try to compensate with soft springs and low oil levels. That formula just doesn't work. In the rocks and roots, the fork has very poor response despite the soft springs, and when you start hitting a series of jumps and whoops the springs are too soft.
I think the stock 250 fork settings are better suited for road use - the bike was a dual sport in some markets.
The stock fork springs are 0.35 kg/mm. Most guys replace with 0.40 to 0.42. After you revalve, the bike will be much more plush on rocks and roots, even with the stiffer springs. I had good luck with Race Tech Gold Valves, which allow much more oil to flow. You really can't compare the RT valving stack with the stock fork due to the vastly different oil flow.
I modified mine 6 years or so ago - other companies besides RT have advanced the state of the art and can certainly do a good job on your suspension.
The stock rear valving and spring are are much better than the fork, but if you need to rebuild it anyway, a revalve does offer some improvement. I also used a Race Tech Gold Valve in the rear on mine, and was pleased. On the rear, I think you can work with the stock valve and maybe try to add a little bit of rebound damping and slightly reduce the high speed compression damping.
In both cases, I used valving that my buddy with a KDX 250 had developed through experimentation, although RT does offer suggestions.
If you are going to play with the fork valve shims yourself, I would focus on reducing high speed compression damping. However, the stock base valve has very small holes and the oil restriction may be a big part of the problem.
Since it takes a lot of time to experiment and disassemble the forks, you may consider sending them off to a shop like MX-Tech or Factory Connection, or find a local guy who does good work.
Best of luck to you - IMO the KDX250 was never properly appreciated. It makes a good bike with a few minor mods.
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