Engine - Yamaha YZ250 2022 Owner's Service Manual

ENGINE REMOVAL ..........................................................................................5-1
REMOVING THE ENGINE .........................................................................5-3
INSTALLING THE ENGINE ........................................................................5-3
CYLINDER HEAD, CYLINDER AND PISTON .................................................5-4
REMOVING THE CYLINDER HEAD ..........................................................5-6
REMOVING THE PUSH ROD ....................................................................5-6
REMOVING THE PISTON..........................................................................5-6
CHECKING THE CYLINDER HEAD ..........................................................5-7
CHECKING THE CYLINDER AND PISTON...............................................5-7
COMBINATION OF PISTON AND CYLINDER ..........................................5-8
CHECKING THE PISTON RING ................................................................5-9
CHECKING THE PISTON PIN ...................................................................5-9
CHECKING THE SMALL END BEARING ................................................5-10
CHECKING THE POWER VALVE ...........................................................5-10
CHECKING THE POWER VALVE HOLE ON CYLINDER .......................5-10
ASSEMBLING THE POWER VALVE .......................................................5-10
INSTALLING THE PISTON AND CYLINDER ..........................................5-12
INSTALLING THE CYLINDER HEAD ......................................................5-14
CDI MAGNETO ...............................................................................................5-15
REMOVING THE ROTOR ........................................................................5-16
CHECKING THE CDI MAGNETO ............................................................5-16
CHECKING THE WOODRUFF KEY ........................................................5-16
INSTALLING THE CDI MAGNETO ..........................................................5-16
KICKSTARTER ...............................................................................................5-18
REMOVING THE PRIMARY DRIVE GEAR .............................................5-19
REMOVING THE KICK SHAFT ASSEMBLY ...........................................5-19
CHECKING THE KICK SHAFT AND RATCHET WHEEL ........................5-19
CHECKING THE KICK GEAR, KICK IDLE GEAR AND RATCHET
WHEEL ....................................................................................................5-19
INSTALLING THE KICK SHAFT ASSEMBLY ..........................................5-19
INSTALLING THE KICK IDLE GEAR .......................................................5-20
INSTALLING THE PRIMARY DRIVE GEAR ............................................5-21
INSTALLING THE KICKSTARTER LEVER..............................................5-21
YPVS GOVERNOR .........................................................................................5-22
REMOVING THE GOVERNOR ................................................................5-23
CHECKING THE GOVERNOR GROOVE ................................................5-23
CHECKING THE BEARING .....................................................................5-23
INSTALLING THE GOVERNOR...............................................................5-23
CLUTCH..........................................................................................................5-25
REMOVING THE CLUTCH ......................................................................5-27
CHECKING THE FRICTION PLATES ......................................................5-27
CHECKING THE CLUTCH PLATES ........................................................5-27

ENGINE

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