6. CYLINDER HEAD/VALVES ZING II 125 SERVICE INFORMATION GENERAL INSTRUCTIONS · The cylinder head can be serviced with the engine installed in the frame. · When assembling, apply molybdenum disulfide grease or engine oil to the valve guide movable parts and valve arm sliding surfaces for initial lubrication. · The valve rocker arms are lubricated by engine oil through the cylinder head engine oil passages. Clean and unclog the oil passages before assembling the cylinder head. · After disassembly, clean the removed parts and dry them with compressed air before inspection. · After removal, mark and arrange the removed parts in order. When assembling, install them in the reverse order of removal. SPECIFICATIONS Standard (mm) Service Limit (mm) Item 125 cc 125 cc Valve clearance (cold) IN 0.06 EX 0.06 Cylinder head compression pressure 14 kg/cm 8 kg/cm Cylinder head warpage 0.05 Camshaft cam height IN 30.80030.920 30.75 EX 30.41130.531 30.26 Valve rocker arm I.D. IN 12.0012.015 12.10 EX 12.0012.015 12.10 Valve rocker arm shaft IN 12.0011.980 11.90 O.D. EX 12.0011.980 11.90 Valve seat angle IN 89° ~ 90° 90° EX 89° ~ 90° 90° Valve stem O.D. IN 5.005.012 4.925 EX 5.00 4.925 Valve guide I.D. IN 5.005.012 5.03 EX 5.005.012 5.03 Valve stem-to-guide IN 0.0100.037 0.08 Clearance EX 0.0300.057 0.10 6-2