Engine - Yamaha YZ125 2022 Owner's Service Manual

ENGINE REMOVAL ..........................................................................................5-1
REMOVING THE ENGINE .........................................................................5-4
INSTALLING THE ENGINE ........................................................................5-4
INSTALLING THE EXHAUST PIPE AND MUFFLER .................................5-4
CYLINDER HEAD, CYLINDER AND PISTON .................................................5-6
REMOVING THE CYLINDER HEAD ..........................................................5-8
REMOVING THE PUSH ROD ....................................................................5-8
REMOVING THE PISTON..........................................................................5-8
CHECKING THE CYLINDER HEAD ..........................................................5-9
CHECKING THE CYLINDER AND PISTON...............................................5-9
COMBINATION OF PISTON AND CYLINDER ........................................5-10
CHECKING THE PISTON RING ..............................................................5-11
CHECKING THE PISTON PIN .................................................................5-11
CHECKING THE SMALL END BEARING ................................................5-12
CHECKING THE POWER VALVE ...........................................................5-12
CHECKING THE POWER VALVE HOLE ON CYLINDER .......................5-12
ASSEMBLING THE POWER VALVE .......................................................5-12
INSTALLING THE PISTON AND CYLINDER ..........................................5-13
INSTALLING THE CYLINDER HEAD ......................................................5-15
CDI MAGNETO ...............................................................................................5-16
REMOVING THE ROTOR ........................................................................5-17
CHECKING THE CDI MAGNETO ............................................................5-17
CHECKING THE WOODRUFF KEY ........................................................5-17
INSTALLING THE CDI MAGNETO ..........................................................5-17
KICKSTARTER ...............................................................................................5-20
REMOVING THE PRIMARY DRIVE GEAR .............................................5-22
REMOVING THE KICK SHAFT ASSEMBLY ...........................................5-22
CHECKING THE KICK GEAR AND KICK IDLE GEAR ............................5-22
INSTALLING THE KICK SHAFT ASSEMBLY ..........................................5-22
INSTALLING THE KICK IDLE GEAR .......................................................5-23
INSTALLING THE PRIMARY DRIVE GEAR ............................................5-23
INSTALLING THE KICKSTARTER LEVER..............................................5-24
YPVS GOVERNOR .........................................................................................5-25
REMOVING THE GOVERNOR ................................................................5-26
CHECKING THE GOVERNOR GROOVE ................................................5-26
CHECKING THE BEARING .....................................................................5-26
INSTALLING THE GOVERNOR...............................................................5-26
CLUTCH..........................................................................................................5-28
REMOVING THE CLUTCH ......................................................................5-30
CHECKING THE FRICTION PLATES ......................................................5-30
CHECKING THE CLUTCH PLATES ........................................................5-30
CHECKING THE CLUTCH SPRINGS ......................................................5-30

ENGINE

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