My wr400 is popping real bad when I chop the throttle while in the 1/4 - 3/4 part of the throttle. I think this is an issue of changing the needle clip position. Should I go richer or leaner? I just opened up my airbox, and put on an after market pipe, and reoiled my air filter. I have pilot at #50, main at #170, needle clip at the 3rd spot.