Set the needles to stock. I find most 3ws the sweet spot on the low end is when you first start it, and the motor is cold, if you transition the throttle quickly just after starting and it stumbles like its lean, wait 30 sec to warm up or so and after warming up it now takes the throttle perfectly, thats a good spot for the low end. High end I set by temping the motor. Since yours has painted heads 220-240 is a good place to set them, then back up check I check the color of the spark plug, and also make sure it does not sag going vertical at all. I typically only move the needles between 1/16 and 1/8th at the most initially.