mxu 250 300 Workshop-manual : Page 119

          7. CYLINDER HEAD/VALVES                                                             MXU 300/250


 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, valve arm and camshaft sliding surfaces for initial lubrication.
 · The camshaft is 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                                                                 Unit mm (in)
                 Item                               Standard                Service Limit
                              IN       0.1 (0.004)                                
 Valve clearance (cold)
                              EX       0.1 (0.004)                                
 Cylinder head     MXU 250             152 kgf/cm (1500 kPa, 213 psi)             
 compression       MXU 300             162 kgf/cm (1600 kPa, 227 psi)             
 Cylinder head warpage                                                    0.05 (0.0002)
                               IN      34.287 (1.3715)                    34.15 (1.366)
 Camshaft cam height
                               EX      34.1721 (1.3669)                   34.05 (1.362)
 Valve rocker arm to shaft clearance   0.0340.09 (0.00140.0036)           0.1 (0.004)
 Valve stem-to-guide           IN      0.010.037 (0.0040.0015)            0.06 (0.0024)
 Clearance                     EX      0.0250.052 (0.0010.0021)           0.08 0.0032)
                               IN      30.9 (1.236)                       29.4 (1.176)
 Valve spring free length
                               EX      41 (1.64)                          39 (1.56)
 Valve spring                  IN      10.2011.84kg(at 18.05mm)                   
 compressed force              EX      19.1422.02kg(at 21.5mm)                    
                               IN      0.8 (0.032)                                
 Valve spring tilt
                               EX      1.07 (0.0428)                              




 TORQUE VALUES
 Cylinder head cover bolt        1 kgf-m ( 10 Nm, 7.2 lbf-ft)
 Cam shaft hold nut              2.5 kgf-m (25 Nm, 18 lbf-ft)    Apply engine oil to threads
 Tappet adjusting nut            0.9 kgf-m (9 Nm, 6.5 lbf-ft)


 SPECIAL TOOLS
 Valve spring compressor            E040
 Tappet adjuster                    E012




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