8. Lubrication system
153
8.2 Lube oil pump
8.2.1 Lube oil pump construction
The trochoid type lube oil pump is mounted in the gear
case, and the inner rotor is driven by the crankshaft
pulley.
The lube oil flows from the intake filter mounted on the
bottom of the cylinder body through the holes in the
cylinder body and engine plate, and out from the holes
in the engine plate and cylinder body to the discharge
filter.
The lube oil pump is fitted with a control valve, which
controls the discharge oil pressure at the specified
pressure.
8.2.2 Specifications of lube oil pump
8.2.3 Lube oil pump disassembly and reassembly
Disassembly
(1) Remove the crankshaft pulley.
(2) Remove the gear case cover.
(3) Remove the lube oil pump cover from the gear case cover. Do not disassemble the
inner /outer rotors, and check that the pump rotates smoothly.
(4) Remove the pressure control valve from the lube oil pump cover.
Note :
Only wash the control valve. Disassembly is unnecessary unless any abnormality in operation is
detected.
Reassembly
[NOTICE]
Always check if the pump rotates smoothly after installation on the gear case.
Running the engine when the pump rotation is heavy may cause the pump to be burnt.
(1) Apply lube oil to rotor (outer/inner) insertion part.
(2) Fasten the pump cover by the standard torque.
(3) When replacing the lube oil pump, replace the whole assy.
Lube oil pump specifications
Engine speed
3600 (min
-1
)
800 (min
-1
)
Pump speed
3477 (min
-1
)
772 (min
-1
)
Delivery quantity
º
19.0 (l/ min
-1
)
º
8.0 (l/ min
-1
)
Delivery pressure
0.43 MPa (4.4 kgf/cm
2
)
º
0.049 MPa (0.5 kgf/cm
2
)
Oil temp.
60±5 (°C)
I
Tightening torque
5.9-7.9 N•m
(0.6-0.8 kgf•m)
Cover
Control
valve
Outer rotor
Inner rotor
Gear case cover
Crankshaft pulley
Summary of Contents for 3YM20
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