Is the engine spank brand new? If not, was it broken in at all and how? Basically the procedure is to set the high speed needle first. Use a tach if you have to and set it for peak, then back it off a couple of hundred rpm for now. Once that is done, set the low end so that when the throttle is advanced in a normal manner the engine transitions cleanly. There are several other factors to consider such as tank location and height above the needle centerline. Let's get some basic info first_bob