- May 17, 2000
I had my bike jetted perfectly with my stock pipe, great throttle response and coco brown plug. I installed an FMF REV pipe on my Y2K KDX 200 over the winter and had it out for the first time this weekend. The bike absolutly rips when I hit the midrange and lofts the front end when holding WOT :) But the off idle throttle response has disappeared. I understand that a REV pipe will steal some Low end for improved top end but I think this is more of a pilot circuit jetting issue. I had the a/f screw @ 1/4 turn out for best performance which indicated that I need a larger pilot. To help me jet the bike I would like to know exactly what caused my pilot circuit to lean out with a pipe change. The only thing I can think of is the intake velocity @ low RPM has dropped off requiring a richer pilot to compensate. Is this correct or is there something else I'm missing??