stock main and turn the air screw out 2 turns with needle in position 4. 48 pilot works for me Good luck 165 is stock for my 06' wr450 I installed the GYTR AIS removal kit per the instructions. The needle and 48 pilot jet are the only things that have been changed in the carb. I did install a Zip Ty air/fuel screw and have it turned out 2 3/4. I ride from sea level to 5000' in 50 to 90 degrees. My bike runs great with smooth power through the range and no decel popping. Everything else is stock.