KDX 250 1991 Model E1 (New Rider)

[doogle]

Hi I have a KDX 250 1991 Model E1 and I have just rebuilt bottom and top. however the bike seems to be fouling plugs and runiing way to rich. The main jet is a 185 any help would be greatly appreciated.

 

[boyo]

Welcome!
I also own a 250 KDX but 93'er.
I think 185 is far too rich ( if stock ) My baby was too lean 144er jet.
After surfing in this forum I could see that the most used jets are betw152 and 165.
By my bike I installed 155 main and 38 pilot ( of course after two days playing with plugchop...etc.) but in wintertime 158 and 40 is the best for me.
I have a SPES pipe but everythink else is stock.
Greetings fom Hungary

 

[doogle]

Excellent thanks for the info.

I have a pilt jet of 38 already just need to change main jet I spose.

 

[Dogz]

I tried a 160 main and 40 pilot with stock needle, fmf pipe no airbox cover, and I had a real bad lean spot at upper midrange, it just bogged, I put the 165 (stock) back in with clip in top position, my bottom end is better, but I'm to rich at the top. I'm going to try a richer needle with the 160 main and see what happens. I did run the clip in its lowest position with the 160 main and it was still way lean in the upper midrange.

 

[dirt bike dave]

The KDX250 also benefits from a leaner slide.  You can buy a new slide with 1mm more cutaway or file approximately 1mm off the bottom of your stock slide.

Most guys run a plug that is one or two steps hotter than the BR9ES Kawaski recommends.

 

[doogle]

Thanks for all your info

I have a 175 to try and put in it but prob will have to go lower by the sounds of it.