KDX 250 Carb question

[bweymouth]

I have a 1992 KDX250. When I bought it (used), it was running very very rich. The main jet was a 160 and I changed it to a 158. Also, I moved the jet needle to the 1st position. The bike runs alot better but now it idles a little too high. How can I bring the idle down a bit?? Should I change the pilot jet? :bang:

Also, should I change the jet needle as it is on the 1st position? Please let me know. Thanks!!

 

[dirt bike dave]

The KDX 250 is jetted extremely rich stock. You will want to lean the main to a 155 or 158, put in a leaner needle (higher #), put in a smaller pilot jet (#38, I think) and if you really want the most out of it, you will want a slide with 1mm more cutaway (you can grind 1mm off your stock slike or purchase a new slide). One of the members in the KDX section (Duc748, I think) has assembled alot of useful information on setting up the KDX250, including many of the tips I used on my '91. Next time you do a top end, get a thinner head gasket from an '88 KX250 for more compression and better low end power.

 

[bweymouth]

Thanks, I just ordered the new needle. The parts guy told me that the stock needle is a #1368 and to go leaner I would need a 1367. Is that correct? Your reply tells me to go to a higher number. Please let me know which is correct.

Thanks!

 

[43Duc748]

1367 is the one you want. If you do a search of this site you will find a lot of good info on the 250, however, I've compiled most of it here:

http://www.garage.whatburns.com/KDX2.htm

You can also adjust the idle using the idle screw (not the air screw). The idle screw is the one w/ the spring.

 

[bweymouth]

Thanks, I'll get it on order.