I HAVE DONE A SEARCH AND NOT FOUND A DEFINATE ANSWER! I AM CALLING ALL JETTING GURU'S I have recently switch my 02WR426 to YZ timing and YZ exhaust. I am running an EKN needle in 4th clip, 160MJ, 160 MAJ, 38PJ, 65PAJ and fuel screw at 1.5 turns out! The bike rips once opened up, but when cruising at a steady pace it wants to hesitate and has minor popping. It does not sound like it is running smoothly and you can feel the hesitation come on and off. I do not really notice it on the trails, except real low rpms. I mainly notice it when I jump on the road coming home! It is most noticeable at roughly one third to half throttle. Do I need to raise the needle one clip?