Yamaha WR250FM service manual Primary drive gear Nut primary drive gear

BALANCER

ENG

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

T.

R.

50 Nm (5.0 m · kg, 36 ft · lb)

•Primary drive gear 3

•Nut (primary drive gear) 4

T.

R.

75 Nm (7.5 m · kg, 54 ft · lb)

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.

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