ENGINE 3-33 • Remove the oil seal 8 and spring seat 9.  Do not reuse the removed oil seal. • Remove the other valves in the same manner as described previously. CYLINDER HEAD DISTORTION • Decarbonize the combustion chambers. • Check the gasketed surface of the cylinder head for distortion with a straightedge and thickness gauge, taking a clearance reading at several places indicated. • If the largest reading at any position of the straightedge exceeds the limit, replace the cylinder head. Cylinder head distortion: Service Limit: 0.20 mm (0.008 in) 09900-20803: Thickness gauge E VALVE STEM RUNOUT L • Support the valve using V-blocks and check its runout using the dial gauge as shown. P • If the runout exceeds the service limit, replace the valve. Valve stem runout: M Service Limit: 0.05 mm (0.002 in) A 09900-20607: Dial gauge (1/100 mm) 09900-20701: Magnetic stand S 09900-21304: V-block set (100 mm)  Be careful not to damage the valve and valve stem when handling it. VALVE HEAD RADIAL RUNOUT • Place the dial gauge at a right angle to the valve head face and measure the valve head radial runout. • If it measures more than the service limit, replace the valve. Valve head radial runout: Service Limit: 0.03 mm (0.001 in) 09900-20607: Dial gauge (1/100 mm) 09900-20701: Magnetic stand 09900-21304: V-block set (100 mm)  Be careful not to damage the valve and valve stem when handling it.