Yamaha YBR250 2007 Service Manual page 189

REMOVING THE ENGINE ........................................................................ 5-1
MUFFLER AND EXHAUST PIPE ....................................................... 5-1
LEADS, CABLES, HOSES AND IGNITION COIL ............................. 5-2
ENGINE .............................................................................................. 5-4
INSTALLING THE ENGINE ................................................................ 5-6
CYLINDER HEAD ..................................................................................... 5-7
REMOVING THE CYLINDER HEAD .................................................. 5-9
CHECKING THE CYLINDER HEAD ................................................ 5-10
CHECKING THE TAPPET COVERS AND CAMSHAFT
SPROCKET COVER ........................................................................ 5-10
CHECKING THE TIMING CHAIN TENSIONER .............................. 5-11
CHECKING THE CAMSHAFT SPROCKET .................................... 5-11
INSTALLING THE CYLINDER HEAD ............................................... 5-12
ROCKER ARMS AND CAMSHAFT ...................................................... 5-16
REMOVING THE ROCKER ARMS AND CAMSHAFT .................... 5-17
CHECKING THE CAMSHAFT .......................................................... 5-17
CHECKING THE ROCKER ARMS AND CAMSHAFTS .................. 5-18
INSTALLING THE ROCKER ARMS AND CAMSHAFTS ................. 5-19
VALVES AND VALVE SPRINGS ............................................................ 5-21
REMOVING THE VALVES ................................................................ 5-23
CHECKING THE VALVES AND VALVE GUIDES ............................. 5-24
CHECKING THE VALVE SEAT ......................................................... 5-26
CHECKING THE VALVE SPRINGS ................................................. 5-28
INSTALLING THE VALVES ............................................................... 5-28
CYLINDER AND PISTON ....................................................................... 5-30
REMOVING THE CYLINDER AND PISTON .................................... 5-31
CHECKING THE CYLINDER AND PISTON ................................... 5-31
CHECKING THE PISTON RINGS ................................................... 5-33
CHECKING THE PISTON PIN ........................................................ 5-34
INSTALLING THE CYLINDER AND PISTON ................................... 5-35
CLUTCH .................................................................................................. 5-37
CLUTCH COVER .............................................................................. 5-37
PULL LEVER SHAFT ....................................................................... 5-38
CLUTCH ............................................................................................ 5-39
REMOVING THE CLUTCH ............................................................... 5-41
CHECKING THE PRIMARY DRIVE GEAR ...................................... 5-42
CHECKING THE FRICTION PLATES .............................................. 5-42
CHECKING THE CLUTCH PLATES ................................................ 5-42
CHECKING THE CLUTCH SPRINGS ............................................. 5-43
CHECKING THE CLUTCH HOUSING ............................................ 5-43
CHECKING THE PRESSURE PLATE ............................................. 5-43
CHECKING THE PUSH LEVER SHAFT AND PUSH ROD ............ 5-44
CHECKING THE PRESSURE PLATE ............................................. 5-44
INSTALLING THE CLUTCH .............................................................. 5-44
CHAPTER 5
ENGINE