2003 Polaris ATV Trail Boss 330 Factory Service Manual, Page 36Get this manual
MAINTENANCE
VALVE CLEARANCE
Inspect and adjust valve clearance while the engine is cold and the piston positioned at Top Dead Center (TDC) on compression stroke1Remove the seat2Remove body panels and fuel tank as necessary to gain access to valve cover3Remove the spark plug high tension lead and remove the spark plugCAUTION: Place clean shop towel into the spark plug cavity to prevent dirt from entering4Remove plastic valve plugs
330 Valve Plugs
INTAKE VALVE CLEARANCE ADJUSTMENT
1Insert .006 (.15mm) feeler gauge between end of intake valve stem and clearance adjuster screw2Using ValveClutch Adjuster (PA-44689), loosen adjuster lock nut and turn adjusting knob until there is slight drag on the feeler gauge