250SX Carb Problems

[mtrdud]

I have a 1985 250SX that i recently aquired that I'm having an unusual problem with. I've cleaned and rebuilt a lot of these carbs but I've never had this problem. The trike will only idle with the air needle out completely. It will even run pretty well without it in but not at low speed. With the needle in it will not idle and spits and sputters. Has anybody had this problem? The plug looks real dry carbon colored black when I remove it.

Thanks

[bones200x]

First..Lets find out what you call an "air needle". Is it the screw in side or bottom of carb? If it is, then you have a passage stopped up. Mainly the pilot jet side. It maybe BEFORE or AFTER the pilot jet. The only other thing I can think of is a bad air leak(vacuum). Make sure the carb is clean...

[mtrdud]

It's the Pilot Screw that I am referring to.

[bones200x]

I need to mention this. If you can take the pilot screw out and it runs better? Then the pilot JET is either TOO small or the pilot circut is stopped up. I think you should THROUGHLY clean your carb. Make sure the pilot jet is at least stock size.

[dads]

sounds like clogged air/fuel passage. in the second dairy jet and pilot screw.