grand dink 250 Workshop-manual : Page 65

          6. CYLINDER HEAD/VALVES                                                      GRAND DINK 250


 SERVICE INFORMATION
 GENERAL INSTRUCTIONS
 · The cylinder head can be serviced with the engine installed in the frame. Coolant in the radiator
   and water jacket must be drained first.
 · 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                                  SH50DA                       SH50DA
 Valve clearance (cold)      IN                         0.10                           
                             EX                         0.10                           
 Cylinder head compression pressure                  15kg/cm                           
 Cylinder head warpage                                                                0.05
 Camshaft cam height         IN                       34.2987                        34.14
                             EX                       34.1721                        34.02
 Valve rocker arm I.D.       IN                   10.0010.015                        10.10
                             EX                   10.0010.015                        10.10
 Valve rocker arm shaft      IN                    9.9729.987                          9.9
 O.D.                        EX                    9.9729.987                          9.9
 Valve seat width            IN                         1.2                           1.8
                             EX                          1.2                           1.8
 Valve stem O.D.             IN                    4.9904.975                        4.925
                             EX                    4.9704.955                        4.915
 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

 TORQUE VALUES
 Cylinder head cap nut           24.5N-m                          Apply engine oil to threads
 Valve clearance adjusting nut   8.8N-m                           Apply engine oil to threads
 Cylinder head cover bolt        7.811.8N-m

 SPECIAL TOOLS
 Valve spring compressor
 Valve seat cutter, 24.5mm                                        45° IN-EX
 Valve seat cutter, 25mm                                          Plane cutter 37.5° EX
 Valve seat cutter, 22mm                                          Plane cutter 37.5° EX
 Valve seat cutter, 26mm                                          Plane cutter 63.5° IN/EX
 Cutter clip
 Valve guide driver
 Valve guide reamer



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