grand dink 125 mmc Manuel atelier : Page 80

          7. CYLINDER/PISTON                                                                      GRAND DINK 125/150



 SERVICE INFORMATION
 GENERAL INSTRUCTIONS
 · The cylinder and piston can be serviced with the engine installed in the frame.
 · When installing the cylinder, use a new cylinder gasket and make sure that the dowel pins are
   correctly installed.
 · After disassembly, clean the removed parts and dry them with compressed air before inspection.

 SPECIFICATIONS
                                                          Standard (mm)                   Service Limit (mm)
                        Item                           SH30DA       SH25DA                SH30DA SH25DA
                   I.D.                              57.40557.415 52.40052.410               57.50         52.50
                   Warpage                               0.01               0.01             0.05           0.05
     Cylinder
                   Cylindricity                          0.01               0.01             0.05           0.05
                   True roundness                        0.01               0.01             0.05           0.05
                   Ring-to-groove    top             0.0150.050        0.0150.050            0.09           0.09
                   clearance         Second          0.0150.050        0.0150.050            0.09           0.09
                                     top              0.150.30          0.150.30             0.50           0.50
     Piston,       Ring end gap      Second           0.150.30          0.150.30             0.50           0.50
     piston ring                     Oil side rail     0.20.9             0.20.9                             
                   Piston O.D.                       57.37557.395 52.37052.390               57.30         52.30
                                                       9mm from          9mm from      9mm from 9mm from
                   Piston O.D. measuring position    bottom of skirt   bottom of skirt bottom of skirt bottom of skirt
 .                 Piston-to-cylinder clearance      0.0100.040        0.0100.040            0.01           0.01
                   Piston pin hole I.D.              15.00215.008 15.00215.008               15.04         15.04
 Piston pin O.D                                      14.99415.000 14.99415.000               14.96         14.96
 Piston-to-piston pin clearance                      0.0020.014        0.0020.014            0.02           0.02
 Connecting rod small end I.D. bore                  15.01615.034 15.01615.034               15.06         15.06


 TROUBLESHOOTING
 · When hard starting or poor performance at low speed occurs, check the crankcase breather for
   white smoke. If white smoke is found, it means that the piston rings are worn, stuck or broken.

 Compression too low or uneven
 compression                                              Excessive smoke from exhaust muffler
 · Worn or damaged cylinder and piston rings              · Worn or damaged piston rings
 · Worn, stuck or broken piston rings                     · Worn or damaged cylinder and piston

 Compression too high                                     Abnormal noisy piston
 · Excessive carbon build-up in combustion                · Worn cylinder, piston and piston rings
   chamber or on piston head                              · Worn piston pin hole and piston pin
                                                          · Incorrectly installed piston




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