Yamaha YZ250F Owner's Service Manual page 165

BALANCER
ASSEMBLY AND INSTALLATION
Balancer shaft, balancer shaft drive gear
and balancer shaft driven gear
1. Install:
• Balancer shaft 1
NOTE:
• Apply the engine oil on the bearing.
• When installing the balancer shaft, align the
center a of the balancer shaft weight along
the line connecting the centers of the crank-
shaft and balancer shaft.
2. Install:
• Balancer shaft driven gear 1
NOTE:
Install the balancer shaft driven gear onto the
balancer shaft while aligning the punch mark
a on the balancer shaft driven gear with the
lower spline b on the balancer shaft end.
3. Install:
• Balancer shaft drive gear 1
NOTE:
• Align the punched mark a on the balancer
shaft drive gear with the punched mark b on
the balancer shaft driven gear 2.
• Align the punched mark c on the balancer
shaft drive gear with the lower spline d on
the crankshaft end.
4. Install:
• Lock washer 1
• Nut (balancer shaft driven gear) 2
• Primary drive gear 3
• Nut (primary drive gear) 4
NOTE:
• Install the primary drive gear with its stepped
side a facing the engine.
• Place an aluminum plate b between the
teeth of the balancer shaft drive gear 5 and
driven gear 6.
5. Bend the lock washer tab.
4 - 65
ENG
50 Nm (5.0 m · kg, 36 ft · lb)
75 Nm (7.5 m · kg, 54 ft · lb)