Jetting help with 04 kx 250

[windyhill]

This bike is trail ridden only, and with my current setup is smoking and drooling like mad. Right now I'm running a 42 pilot, NAFG needle(2nd clip position), 158 main, stock power jet,air screw at 1.5 turns, Q-silencer, and 40:1 honda syn. oil on pump gas. The NAFG needle is almost the leanest one available per the ones listed in the manual. Tranny oil is fine. I'm thinking two things here, either the power jet is to rich or the needle taper is not correct for trail riding . Any suggestions would be greatly appreciated, Thanks John.

 

[toddb3]

Have you tried turning out the air screw to lean it?

 

[j32]

drooling oil !!-use klotz 40:1-
bigger jets will allow more fuel and oil!!! in the cylinder
smaller will reduce it but it wont help burn crappy oil/or too much oil in the fuel -it is not oil injected
clean the air filter
change the silencer packing ,it is pabably full of oil and is clogging up the exhaust
check the reeds-new boeysen pro series are great,follow the directions
mabe a 45 pilot and 2 turns out on the air screw

 

[KX02]

You might want to try a James Dean jetting kit for your bike. I put one in my KX and it runs great and does not spooge or foul plugs.

 

[KDX CRAZY]

Dont take this the wrong way , but maybe you have the wrong bike for your riding .

I have mates with kx's standard jetting and 32 to 1 mixture with very little spooge , but they really ride the bikes , these are race machines designed to be revved .If you dont get to rev the bike up , it is going to have to be set in extremely lean to ride and then when you do ride it hard one day you could have a problem with heat siezing it .

Dont change your oil mix to try fixing a jetting problem .

 

[Britt Boyette]

Check out this jetting link.

http://www.all-offroad.com/DirtBikes/Beginners/BGNov98.html

 

[windyhill]

Thanks for all the suggestions guys, I am definately going to stick with the honda oil at 40:1. That JD jet kit is beginning to sound better all the time although I am going to try one more thing before I spend the $60. I ordered a #45 power jet(stock is 50) from the Kawi dealer the other day. My reasoning is that while trail riding I spend alot of time going from closed throttle to about half throttle.I believe half throttle is when the power jet is dumping fuel into the circuit. I know the bike wasn't designed for this type of riding, but I still wouldn't trade it for anything else, this thing has been very reliable so far.

 

[Britt Boyette]

One other thing you might want to consider doing to your bike is adding a flywheel weight to it. It takes out the low speed loping and makes it a little more 4 stroke like. Plus, I can start my KX250 in one kick cold.