KDX 220 jetting

[TomDez]

I am going from bone stock to the following mod's.What jetting would you recommend?
2001 KDX 220-adding FMF Gnarky rev pipe, staying with stock silencer,airbox lid removed. Would the jetting be different for fall and summer (I ride in northern illinois). Also, would adding a FMF silencer change jetting or performance?

 

[R. Phillips]

Tom:
I too have an 01' kdx220. I was runing rich and fouling plugs when it was stock. I went to a 142 main and 38 pilot. This helped, but still seemed rich. I then put on a Pro Circuit pipe and spark arrestor, and drilled my airbox lid.

The pipe and air box mod leaned the bike out to a what I call "good" operation. So your FMF should lean it some. (I don't think the air box mod had much affect)

This was in August when temps were in the 90's. Last weekend I rode with temps in the 50's and bike was bogging due to it being too lean now.

I don't think anyone can tell you what will work in your bike, but this may be a start.

I have come to the conclusion that if you own a kdx you need to buy at least 2 sizes up and 2 sizes down from stock jets, and tinker as needed.

One suggestion, find a good oil (Mobil 1 MX 2T is very popular) and stick with one mix i.e. 40:1. Every tweak I did affected something else.

 

[canyncarvr]

CDave has jetting recs for various mods-as-you-go. You've been there?

http://justkdx.dirtrider.net

<tech tips> <carb tuning>

I don't think anyone can tell you what will work in your bike, but this may be a start

AMEN!!