I found some instructions online that made sense to me. First, dial in the low speed needle, then the high speed. The instructions say to turn in the high speed until the bike backfires through the carb after a short run at cruising speed, followed by a complete closing of the throttle. When this occurs, turn the high speed out 5 clicks. Then return to the low speed, and take that out another three clicks, the reason being that both adjustments affect each other.