KDXRIDER.NET

hello all, i spoke to the previous owner of my bike ( he bought it new in 1998), and he said he never touched the jetting so it was stock. i feel that it runs a little rich. i am installing a fmf woods pipe on wednesday and adding the silencer in the next couple of weeks. i know i need to re jet for sure, but i also don't want to spend $62 bucks for the jd jetting kit if i'm only going to use one of the jets it comes with. here is what i have:

1998 KDX 200
stock jetting
fmf woods expansion chamber
stock gearing
i mainly ride capital forest in western washington
it's tight and technical
i was thinking of ordering a 150, 152, 155 main jet
i just want to confirm this, i know some guys ride the same stuff i do and can help ball park me, thanks

I'd forget about the JD kit for that price. Get some smaller pilot jets 38, 40, 42, 45 too.

Thank you for your help. I just hope it'll run ok with that pipe until I get the jets in and find somewhere with a long straight so I can jet properly

Honestly, (and I might get flamed for this, lol), the plug chops are about the least important part of jetting if you are trail riding. As long as your main isn't rich enough to be fouling plugs or lean enough where it's bogging at full throttle it's going to be fine. I mean, honestly, how much time do you spend holding the throttle wide open?

It's pretty easy to work on the pilot and needle. Mark your throttle openings, ride at those, and pay attention to how it feels.

As for a ballpark, 45/155 stock needle in middle position is a pretty safe starting point for most people.

I'm with you on that one. If you're riding fast trail (desert, fire road, street...) with long wide open throttle then it'd be an issue.

That's the thing we ride long ride open fire roads out to the single track at capital forest.

Then yeah, might be more important to you than most KDX riders. But even then, next time you're ripping up a fire road, pay attention to how long you spend actually at more than 3/4 throttle. I bet it's less than you think.

I could always jet as much as I can. Then when I go out to the fire roads, do some runs to dial it in

if the jetting is indeed stock I'd bet you'd be pretty close (i.e: safe) with your new pipe, probably still on the rich side still...
Just follow the guide and it'll be evident if you're good or not.