Please advise, Need carb help

[javo]

Ive got a 1996 KX 250. Im running 45:1 and Im fouling plugs like crazy. The bike starts fine and rins fine for a while, but if I park it for 10 minutes or so and start it back up I can get about 1/2 mile from the truck and it fouls the plug. I have the Keihn Carb with a 160 mainjet in it. Im in Texas where it around 100 degrees and 65% humidity until October. What main jet do I need? My buddy is running a 162 in his KX 250 but I would think that would waste more plugs. I could be wrong though.

Thanks,
Jason

 

[Stew312]

I'de try a 32:1 mix with a leaner main jet.

 

[javo]

I bought a 155 but havent ridden yet will this be too lean?

 

[helio]

Try only a size leaner and ride...Still rich ? then another 1 size leaner...
If you go 2 or more sizes leaner for first time without riding and feel the effects of the modification you can seize the piston...
I'de try 32:1 mix with fresh gas, clean air filter(dirt i the filter can cause a rich condition in jetting) and one notch leaner in needle.

Only my thought.

 

[Stew312]

go with the 155, that'll do.

 

[javo]

Thanks for the info.. I went ahead and bought a 158 just in case the 155 is too lean.. Im going riding this weekend and dont need any hold-ups.

Thanks again,
Jason

 

[marcusgunby]

i would look at all the carb circuits before changing the main(its more likely the needle or pilot).Eric gorrs website has a good jetting guide.

 

[Durt Cycler]

I would do a few plug test, try lowering the clip position, and down on the main jet. If you don't have much luck try going to a 32:1 mix and see.