Engine - Yamaha WR125R 2009 Service Manual

ENGINE REMOVAL ........................................................................................ 5-1
REMOVING THE ENGINE ........................................................................ 5-5
INSTALLING THE ENGINE....................................................................... 5-5
INSTALLING THE RIDER FOOTREST/BRAKE PEDAL BRACKET
ASSEMBLY .............................................................................................. 5-5
INSTALLING THE SHIFT PEDAL ............................................................. 5-6
INSTALLING THE MUFFLER AND EXHAUST PIPE................................ 5-6
CYLINDER HEAD............................................................................................ 5-7
REMOVING THE CYLINDER HEAD......................................................... 5-9
CHECKING THE CYLINDER HEAD ......................................................... 5-9
CHECKING THE CAMSHAFT SPROCKET AND TIMING
CHAIN GUIDE ........................................................................................ 5-10
CHECKING THE TIMING CHAIN TENSIONER...................................... 5-10
CHECKING THE DECOMPRESSION SYSTEM..................................... 5-11
INSTALLING THE CYLINDER HEAD ..................................................... 5-11
CAMSHAFT ................................................................................................... 5-14
CHECKING THE CAMSHAFT................................................................. 5-15
CHECKING THE ROCKER ARMS AND ROCKER ARM SHAFTS ........ 5-15
INSTALLING THE CAMSHAFT AND ROCKER ARMS .......................... 5-16
VALVES AND VALVE SPRINGS.................................................................. 5-17
REMOVING THE VALVES...................................................................... 5-18
CHECKING THE VALVES AND VALVE GUIDES .................................. 5-18
CHECKING THE VALVE SEATS ............................................................ 5-20
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
GENERATOR AND STARTER CLUTCH...................................................... 5-29
REMOVING THE GENERATOR ............................................................. 5-31
REMOVING THE STARTER CLUTCH ................................................... 5-31
CHECKING THE STARTER CLUTCH .................................................... 5-32
INSTALLING THE STARTER CLUTCH .................................................. 5-32
INSTALLING THE GENERATOR............................................................ 5-32
ELECTRIC STARTER ................................................................................... 5-34
CHECKING THE STARTER MOTOR ..................................................... 5-36
ASSEMBLING THE STARTER MOTOR................................................. 5-37

ENGINE

5