How do you adjust the carb on a 1979 Yamaha IT 175?

1979 IT175 Assuming the carb is cleaned properly, adjustments can be made at the pilot air screw for idle mixture adjustments simply by turning the screw to adjust air/fuel ratio. (stock 1 1/4 turns out from bottomed). For mid-range air/fuel ratio adjustments, you can change the clip position at the main needle (stock clip at #4 - fourth groove from the short side). For 3/4 to wide open air/fuel ratio adjustments, change the main jet for something larger or smaller (stock #360). These settings come from the 1979 IT175 owner's manual.