I've got an 88 LT 250 with: a boysen rad valve, and a keihin 34 carb, FMF gold series pipe and silencer, and a K&N filter with no airbox. I'm having jet problems since adding the pipes. In Glamis i used to run stock needle and pilot and a 135 main jet. Now i have no clue it seems super lean on the low end because when I stop the engine races out of control. i had like a 152 in and it didn't seem fat but cut out on the top end. I moved the needle to the top clip and that still didn't seem to do much. I'm not real knowledgable on jetting so should I increase the pilot jet or do I have another problem?
Any feed back on this problem would be helpful.

 

Go to duncan's website Duncan Racing and read there piece on 2-stroke jetting. It sounds like you need to move the needle clip down to richen up the mixture. I would check with duncan to be sure though. I don't have a ton of experience with carbs. I like to let the mechanic do that.