KDXRIDER.NET

The bike: '06 KDX200
Mods done to it:
-FMF Gnarly pipe
-607 Boyesen reeds
-FMF silencer
-'04 KX250F USD fork conversion revalved for 160 lbs
-Airbox lid drilled out

My riding info:
-230 lbs.
-ride in hard pack terrain
-riding ability: experienced C rider

Mods I'll be having done to it shortly:
-RB head (pump gas) & carb
-Shock revalve
-might try a '95 KX125 throttle cable & tube

I bought this bike for my 16 old son so we could go trail riding & maybe do some crosscountry races. Then I bought myself a KX450F so we started to go to the mx track more often. As the time went by my son kept improving at a fast pase & wants to race mx so I've decided to give him my KX450F & take over his KDX200. I'm not into racing but more to ride with him at the track. Also I know the KDX is not intended for mx but I just want to make the bike as close as it can be for a mx track. Here are a few questions I have, but please add anything you may think it will help:

-What gearing should I have?
-What spring rates would I need?
-What will be the max oil capacity I can have in the forks to resist bottoming on big jumps?

*By the way, does the 200's piston grenades in the same way as I've read it happens to the 220?

The stock piston for the KDX200 holds up just fine, so no worries there. It looks like you have most all the mods done or planned that you would want to do. The spring rate depends on your weight. I could go look it up for you, but I'm lazy. Go to racetech and use the spring calculator to figure the correct springs for your weight. With the right spring rates you should not need to use "the maximum amount of oil" or anything.

Other than than replacing the springs with proper rates for your weight it looks like you should have a really fun bike on your hands. With the fork conversion on there it should handle the track quite well. Just ride it!!

Yep, looks like you have all the goodies(or have them planned). When you wear your 607s out get a VForceIII, thats about it. THe 04 KXF forks have to be sweet on the track, eh? Save your $ so you can afford to run the 450F Get the head done, but maybe hold off on the carb. On a MX track you probably won't notice the befefits of the carb 'as much.' Would make sure the susp is setup for MX first.

fuzzy, juliend thanks a lot for your quick replies!!. Any thoughts on what gearing should I try?

I wouldn't change it from stock unless you really feel like you need to. The stock gearing works really well after power mods.