The Honda FourTrax 300EX is a small all-terrain vehicle (ATV) that has a lot to offer. This ATV is a cross between a sport quad and a sportsman. The 300cc four-stroke engine produces a lot of power and torque. Only newer FourTrax 300EX models have fuel injectors; earlier model have carburetors. Adjusting a FourTrax 300EX carburetor is not difficult, but you will need the adjustment chart in the owner’s manual.
Locate the carburetor on the top middle of the engine. Turn the gas valve to the off position. Locate all of the small gold-colored pins on the surface of the carburetor and the small metal screw on the lower bottom right side of the carburetor.