2008 Polaris Sportsman 500 EFI/X2/Touring/500 H.O. Service Manual, Page 148Get this manual
CARBURETORSPORTSMAN 500 When the pressure above and below the diaphragm are nearly equal, the slide moves downward under spring pressureRaising or lowering the slide increases or decreases the cross sectional area in the venturi, and therefore the air velocity in the venturi is kept relatively constantThis provides improved fuel atomization and optimum fuelair ratio
Pilot (Idle and Slow) System
This system supplies fuel during engine operation with throttle valve closed (1) or slightly openedThe fuel from float chamber (2) is metered by pilot jet (3) where it mixes with air coming in through pilot air jet (4)The mixture then goes up through pilot passage to pilot screw (5)A part of the mixture is discharged into the main bore out of bypass ports (6)The remainder is then metered by pilot screw and discharged into the main bore through pilot outlet (7)