kpw 50 Workshop-manual : Page 72

          7. CYLINDER/PISTON                                                                            K-PIPE 50


 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
                         Item                         Standard Limit (mm) Service Limit (mm)
                   I.D.                                                           52.4
                   Warpage                                                        0.05
     Cylinder
                   Cylindricity                                                   0.05
                   True roundness                                                 0.05
                   Ring-to-groove     top                                         0.12
                   clearance          Second                                      0.12
                                      top                  0.10.25                   0.5
     Piston,       Ring end gap       Second               0.10.25                   0.5
     piston ring                      Oil side rail        0.10.25                   0.5
                   Piston O.D.                         55.5855.95                   51.6
                                                     5mm from bottom of   5mm from bottom of skirt
                   Piston O.D. measuring position           skirt
 .                 Piston-to-piston pin clearance      0.0050.014                    0.1
                   Piston pin hole I.D.           0.010.35                          13.00
 Piston pin O.D                                       12.99413.000                 12.944
 Connecting rod small end I.D. bore                   13.01613.034                  13.08


 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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