2003 Polaris ATV Trail Boss 330 Factory Service Manual, Page 63Get this manual
VALVE SEAT RECONDITIONING
Valve Seat Inspection Inspect valve seat in cylinder head for pitting, burnt spots, roughness, and uneven surfaceIf any of the above conditions exist, the valve seat must be reconditionedSee Valve Seat Reconditioning, Page 3.193.21If the valve seat is cracked the cylinder head must be replaced
7Subtract valve stem measurement to obtain stem to guide clearanceNOTE: Be sure to measure each guide and valve combination individually8Replace valve andor guide if clearance is excessiveCompare to specificationsToo Wide Uneven Good Too Narrow
Valve Guide I.D .2362-.2367I (6.0-6.012 mm)