Engine - Yamaha YZ250FM 2021 Owner's Service Manual

LUBRICATION SYSTEM CHART AND DIAGRAMS .......................................5-1
ENGINE OIL LUBRICATION CHART.........................................................5-1
LUBRICATION DIAGRAMS .......................................................................5-2
ENGINE REMOVAL ..........................................................................................5-6
REMOVING THE ENGINE .......................................................................5-11
INSTALLING THE ENGINE ......................................................................5-11
INSTALLING THE EXHAUST PIPE AND MUFFLER ...............................5-12
CAMSHAFT ....................................................................................................5-14
REMOVING THE CAMSHAFT .................................................................5-16
CHECKING THE CAMSHAFT ..................................................................5-17
CHECKING THE TIMING CHAIN AND CAMSHAFT SPROCKET...........5-18
CHECKING THE TIMING CHAIN TENSIONERS.....................................5-18
CHECKING THE DECOMPRESSION SYSTEM ......................................5-18
INSTALLING THE CAMSHAFTS .............................................................5-18
CYLINDER HEAD...........................................................................................5-21
REMOVING THE CYLINDER HEAD ........................................................5-23
CHECKING THE TIMING CHAIN GUIDE (INTAKE SIDE).......................5-23
CHECKING THE CYLINDER HEAD ........................................................5-23
INSTALLING THE CYLINDER HEAD ......................................................5-23
VALVES AND VALVE SPRINGS ....................................................................5-26
REMOVING THE VALVES .......................................................................5-27
CHECKING THE VALVES AND VALVE GUIDES....................................5-28
CHECKING THE VALVE SEATS .............................................................5-29
CHECKING THE VALVE SPRINGS .........................................................5-30
CHECKING THE VALVE LIFTERS ..........................................................5-31
INSTALLING THE VALVES......................................................................5-31
CYLINDER AND PISTON ...............................................................................5-33
REMOVING THE PISTON........................................................................5-34
CHECKING THE CYLINDER AND PISTON.............................................5-34
CHECKING THE PISTON RINGS ............................................................5-35
CHECKING THE PISTON PIN .................................................................5-35
INSTALLING THE PISTON AND CYLINDER ..........................................5-36
GENERATOR..................................................................................................5-38
REMOVING THE GENERATOR ..............................................................5-39
CHECKING THE GENERATOR ...............................................................5-39
CHECKING THE WOODRUFF KEY ........................................................5-39
INSTALLING THE GENERATOR .............................................................5-39
STARTER CLUTCH ........................................................................................5-41
REMOVING THE STARTER CLUTCH.....................................................5-42

ENGINE

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