1999-2004 Suzuki King Quad LT-300 300F ATV Factory Service Manual, Page 68Get this manual
VALVE FACE WEAR Visually inspect each valve face for wearReplace any valve with an abnormally worn faceThe thickness of the valve face decreases as the face wearsMeasure the valve face (j)If it is out of specification replace the valve with new one09900-20102: Vernier calipers
Service Limit Valve face thickness (j): 0.5 mm (0.02 in) VALVE STEM DEFLECTION Lift the valve about 10 mm (0.39 in) from the valve seatMeasure the valve stem deflection in two directions, "X" and "Y", perpendicular to each otherPosition the dial gauge as shownIf the deflection exceeds the service limit, then determine whether the valve or the guide should be replaced with new one
'Mitt 09900-20606: Dial gauge (11100 mm)
09900-20701: Magnetic stand Service Limit Valve stem deflection: 0.35 mm (0.014 in)