1985-1995 Polaris ATV and Light Utility Hauler Service Manual, Page 345Get this manual
ENGINESCARBU RETION Main System The main system is designed to deliver fuel between low speed and high speed operationThis system consists of the jet needle, needle jet, and main jetThe main system begins to take effect as soon as there is enough air flow into the carburetor venturi to draw fuel up through the main jet and needle jet assemblyDuring low speed driving there is very little clearance between the jet needle and the needle jet, so very little fuel from the main jet can pass between the jet needle and the needle jetAs the throttle valve opening is increased, the tapered jet needle is raised farther out of the needle jet, allowing greater fuel flowUnder full throttle opening, the area of clearance between the jet needle and the needle jet becomes greater than the area of the main jetWhen this occurs, the main jet takes control of the amount of fuel flow