Carb settings vary by day, so instead of a fixed needle setting like many 4 cycle guys do, what I did was a pretty simple process.
1.) set needles at factory recommended settings.
2.) take an easy lap to get things up to temp.
3.) at temp, turn LOW needle out until engine bogs on accelleration from low to mid RPM. This is called “4 cycling” because that’s what it sounds like…
4.) Turn LOW needle in very slowly, stopping once the accelleration “cleans up” and is a crisp accelleration from low to mid. I do this slowly to not overshoot this zone and accidentally go too lean.
5.) Repeat the process with the HIGH needle, turn out until it “4 cycles” from mid transition to high rpm. Turn in until accelleration cleans up again.
This will get you into a safe zone, close to the optimum window. From there, you can slowly turn the high needle in to fine tune accelleration. I tune by ear, typically, and found that in the ideal spot, the engine exhaust note is “crisper” than other settings. IT’s kinda’ hard to describle, but there’s almost a “Crack” to the sound but no detonation pinging or other anomalies… Tuning by ear is a lost art now that mychrons are around, I suppose. But it’s a good skill to have since you can do it while racing and spotting your apexes…
Perhaps TJ or someone else more experienced can chime in, but this was (is) my method.