Checking The Crankcase; Checking The Bearing; Checking The Oil Pump Drive Gear; Installing The Crankshaft - Yamaha MBK MW125 2014 Service Manual

3. Measure:
• Crankshaft width
Out of specification → Replace the crank-
shaft assembly.
Crank assembly width
45.45–45.50 mm (1.789–1.791 in)
4. Check:
• Crankshaft sprocket "1"
Damage/wear → Replace the crankshaft as-
sembly.
• Bearing "2"
Cracks/damage/wear → Replace the crank-
shaft assembly.
2
1
EAS31243

CHECKING THE CRANKCASE

1. Thoroughly wash the crankcase halves in a
mild solvent.
2. Thoroughly clean all the gasket surfaces and
crankcase mating surfaces.
3. Check:
• Crankcase
Cracks/damage → Replace.
EAS31244

CHECKING THE BEARING

1. Check:
• Bearing
Clean and lubricate the bearings, and then
rotate the inner race with your finger.
Rough movement → Replace.
EAS31245

CHECKING THE OIL PUMP DRIVE GEAR

1. Check:
• Oil pump drive gear
Damage/wear → Replace.
EAS30791

INSTALLING THE CRANKSHAFT

1. Install:
• Crankshaft assembly "1"
TIP
Install the crankshaft assembly with the crank-
shaft installer pot "2", crankshaft installer bolt "3",
adapter "4", and crankshaft installer spacer "5".
Crankshaft installer pot
90890-01274
Installing pot
YU-90058
Crankshaft installer bolt
90890-01275
Bolt
YU-90060
Adapter (M12)
90890-01278
Adapter #3
YU-90063
Crankshaft installer spacer
90890-04156
1
5
4
ECA13970
NOTICE
To avoid scratching the crankshaft and to
ease the installation procedure, lubricate the
oil seal lips with lithium-soap-based grease
and each bearing with engine oil.
5-65
CRANKSHAFT
2
3