3-34 ENGINE VALVE STEM AND VALVE FACE WEAR CONDITION • Visually inspect each valve stem and valve face for wear and pitting. If it is worn or damaged, replace the valve with a new one. VALVE STEM DEFLECTION • Lift the valve about 10 mm (0.39 in) from the valve seat. • Measure the valve stem deflection in two directions, perpen- dicular to each other, by positioning the dial gauge as shown. • If the deflection measured exceeds the limit, then determine whether the valve or the guide should be replaced with a new one. Valve stem deflection (IN. & EX.): Service Limit: 0.25 mm (0.010 in) 09900-20607: Dial gauge (1/100 mm) E 09900-20701: Magnetic stand L VALVE STEM WEAR • If the valve stem is worn down to the limit, as measured with a micrometer, replace the valve. P • If the stem is within the limit, then replace the guide. M • After replacing valve or guide, be sure to recheck the deflec- tion. A Valve stem O.D.: S Standard (IN.) : 4.475 – 4.490 mm (0.1762 – 0.1768 in) (EX.): 4.455 – 4.470 mm (0.1754 – 0.1760 in) 09900-20205: Micrometer (0 – 25 mm) NOTE: If valve guides have to be removed for replacement after inspecting related parts, carry out the steps shown in valve guide servicing. (3-35)