Yamaha 2009 YFM25RY, Service Manual, Page: 163 / 293

5
ENGINE
ENGINE REMOVAL ......................................................................................5-1
INSTALLING THE ENGINE ....................................................................5-4
INSTALLING THE MUFFLER AND EXHAUST PIPE..............................5-4
CAMSHAFT ..................................................................................................5-6
REMOVING THE ROCKER ARMS AND CAMSHAFT ...........................5-7
CHECKING THE CAMSHAFT ................................................................5-7
CHECKING THE ROCKER ARMS AND ROCKER ARM SHAFTS ........5-8
INSTALLING THE CAMSHAFT AND ROCKER ARMS ..........................5-9
CYLINDER HEAD ....................................................................................... 5-10
REMOVING THE CYLINDER HEAD .................................................... 5-12
CHECKING THE CYLINDER HEAD .................................................... 5-12
CHECKING THE TIMING CHAIN GUIDES .......................................... 5-13
CHECKING THE TIMING CHAIN TENSIONER ................................... 5-13
INSTALLING THE CYLINDER HEAD ................................................... 5-14
VALVES AND VALVE SPRINGS ................................................................ 5-16
REMOVING THE VALVES .................................................................... 5-17
CHECKING THE VALVES AND VALVE GUIDES ................................. 5-17
CHECKING THE VALVE SEATS .......................................................... 5-19
CHECKING THE VALVE SPRINGS...................................................... 5-21
INSTALLING THE VALVES................................................................... 5-22
CYLINDER AND PISTON ........................................................................... 5-24
REMOVING THE PISTON .................................................................... 5-25
CHECKING THE CYLINDER AND PISTON......................................... 5-25
CHECKING THE PISTON RINGS ........................................................ 5-26
CHECKING THE PISTON PIN ............................................................. 5-27
INSTALLING THE PISTON AND CYLINDER ....................................... 5-27
CLUTCH ...................................................................................................... 5-29
REMOVING THE CLUTCH................................................................... 5-32
CHECKING THE FRICTION PLATES .................................................. 5-32
CHECKING THE CLUTCH PLATES..................................................... 5-33
CHECKING THE CLUTCH SPRINGS .................................................. 5-33
CHECKING THE CLUTCH HOUSING ................................................. 5-33
CHECKING THE CLUTCH BOSS ........................................................ 5-33
CHECKING THE PRESSURE PLATE .................................................. 5-34
CHECKING THE CLUTCH PUSH RODS............................................. 5-34
CHECKING THE PRIMARY DRIVE GEAR .......................................... 5-34
INSTALLING THE CLUTCH.................................................................. 5-34
OIL PUMP ................................................................................................... 5-38
REMOVING THE OIL PUMP ................................................................ 5-40
CHECKING THE OIL PUMP ................................................................ 5-40
CHECKING THE BALANCER WEIGHT GEAR.................................... 5-40