Yamaha YZ250FM 2021 Owner's Service Manual

12345678910ENGINELUBRICATION SYSTEM CHART AND DIAGRAMS .......................................5-1ENGINE OIL LUBRICATION CHART.........................................................5-1LUBRICATION DIAGRAMS .......................................................................5-2ENGINE REMOVAL ..........................................................................................5-6REMOVING THE ENGINE .......................................................................5-11INSTALLING THE ENGINE ......................................................................5-11INSTALLING THE EXHAUST PIPE AND MUFFLER ...............................5-12CAMSHAFT ....................................................................................................5-14REMOVING THE CAMSHAFT .................................................................5-16CHECKING THE CAMSHAFT ..................................................................5-17CHECKING THE TIMING CHAIN AND CAMSHAFT SPROCKET...........5-18CHECKING THE TIMING CHAIN TENSIONERS.....................................5-18CHECKING THE DECOMPRESSION SYSTEM ......................................5-18INSTALLING THE CAMSHAFTS .............................................................5-18CYLINDER HEAD...........................................................................................5-21REMOVING THE CYLINDER HEAD ........................................................5-23CHECKING THE TIMING CHAIN GUIDE (INTAKE SIDE).......................5-23CHECKING THE CYLINDER HEAD ........................................................5-23INSTALLING THE CYLINDER HEAD ......................................................5-23VALVES AND VALVE SPRINGS ....................................................................5-26REMOVING THE VALVES .......................................................................5-27CHECKING THE VALVES AND VALVE GUIDES....................................5-28CHECKING THE VALVE SEATS .............................................................5-29CHECKING THE VALVE SPRINGS .........................................................5-30CHECKING THE VALVE LIFTERS ..........................................................5-31INSTALLING THE VALVES......................................................................5-31CYLINDER AND PISTON ...............................................................................5-33REMOVING THE PISTON........................................................................5-34CHECKING THE CYLINDER AND PISTON.............................................5-34CHECKING THE PISTON RINGS ............................................................5-35CHECKING THE PISTON PIN .................................................................5-35INSTALLING THE PISTON AND CYLINDER ..........................................5-36GENERATOR..................................................................................................5-38REMOVING THE GENERATOR ..............................................................5-39CHECKING THE GENERATOR ...............................................................5-39CHECKING THE WOODRUFF KEY ........................................................5-39INSTALLING THE GENERATOR .............................................................5-39STARTER CLUTCH ........................................................................................5-41REMOVING THE STARTER CLUTCH.....................................................5-42