Yamaha BR250F Service Manual page 29

1. Place the washer on the oil pump drive
shaft, and insert the drive shaft into the
oil pump. Be sure the worm gear correct-
ly engages the oil pump gear in the
pump.
2. Secure the pump to the gear case. Use a
new gasket. Apply Yamabond 4 to the
gear case side of the gasket only.
3. Align the hole in the drive shaft with the
slot in the gear case and install the secur-
ing pin.
4. Thoroughly grease the outer edges of the
drive gear onto the oil pump drive shaft.
Be su re the gear correctly engages the
securing pin.
5. Secure the drive gear in place with the
two washers and the snap ring. Be su re
the wave washer is against the drive gear.
6. Grease the edges of the drive gear, and
install the gear case cover.
2-18
7. Install the oil pump gear box onto the
engine. Be sure the drive gear correctly
engages the oil pump drive gear on the
crankshaft. Torque the four securing
bolts to specification.
Tightening torque:
0.68 m-kg (4.9 ft-lb)
Bleeding the Oil Pump
The oil pump must be bled whenever:
Any portion of the oil system has been
disconnected.
The machine has been turned on its side.
Whenever the oil tank has been run
empty.
During predelivery.
There are two methods for bleeding the pump
on this model. Either will work very well.
1. Loosen the bleed screw at the pump. Oil
should begin to flow through the line.
Keep the bleed screw open until all air
has left the fuel Iine. Tighten the bleed
screw.
2. Start the engine and keep it running at
idle. Pull the pump stroke wire all the
way out to set the pump at maximum
stroke. Keep the pump operating at full
stroke for about two minutes. This will
bleed the air from the oil system.