4. Engine Body l Different stem seals are provided for the intake and exhaust valves. Do not confuse them l After assembling the intake/exhaust valve, stem seal, valve spring, seat, and cotter, tap the since those for exhaust valves are marked with yellow paint. head of the valve stem lightly for settling. l Do not forget to install the valve cap. (5) Parts Inspection and measurement (5.1) Cylinder head Clean the cylinder head, mainly the combustion surface, valve seats and intake/exhaust ports, remove carbon deposit and bonding agent, and check the surface state. (a) Appearance check Check mainly discoloration and crack. If crack is suspected, perform color check.
(b) Combustion surface distortion Apply a strait-edge in two diagonal di- rections and on four sides of the cylin- der head, and measure distortion with Distortion at combustion surface a thickness gage. Limit 0-m-d 0.05 or less 0.15 Valve (c)Valve sink Measure with the valve inserted to the cylinder head. Depth micrometer Standard Limit (mm\ 4TNE94.98 Intake 0.5-0.7 1 .o Exhaust 0.6-0.8 1.1 4TNE106 (T) Intake 0.7-0.9 1.2 Exhaust 0.9-1.1 1.4 Valve sink depth Valve sinking depth 4-5