6. CYLINDER HEAD/VALVES ZING II 125 Straight Edge INSPECTION CYLINDER HEAD Check the spark plug hole and valve areas for cracks. Check the cylinder head for warpage with a straight edge and feeler gauge. Service Limit: 0.05mm repair or replace if over Feeler Gauge VALVE SPRING FREE LENGTH Measure the free length of the inner and outer valve springs. Service Limits: (IN, EX) : 29.1mm replace if below VALVE /VALVE GUIDE Inspect each valve for bending, burning, scratches or abnormal stem wear. Check valve movement in the guide. Measure each valve stem O.D. Service Limits: IN 4.925mm replace if below EX 4.925mm replace if below Measure each valve guide I.D. Service Limits: IN 5.03mm replace if over EX 5.03mm replace if over Subtract each valve stem O.D. from the corresponding guide I.D. to obtain the stem- to-guide clearance. Service Limits: IN 0.08mm replace if over EX 0.10mm replace if over If the stem-to-guide clearance exceeds the service limits, replace the guides as necessary. Reface the valve seats whenever the valve guides are replaced. 6-8