The high-speed needle can be opened 2 to 2-1/2 turns out from closed as a starting point. The idle needle should be set so that there's about a 4-5 mm space between the needle and the nozzle when the carb's opened to the full-throttle position. This will be an excessively-rich idle mixture setting. Get the engine started at part throttle, open to full and get the high-speed needle set, and then retard the throttle to work on the low-speed mixture.