Derbi Rambla 250 Manual page 141

Engine
FIT THE BELLEVILLE WASHER SO THAT ITS OUTER RIM
TOUCHES THE PULLEY. MAKE SURE THAT THE PUMP
TURNS FREELY.
Locking torques (N*m)
Screws fixing oil pump to crankcase 5÷6 (3.7÷4.4 ftlb) oil pump driving crown gear screw 10÷14
(7.4÷10.3 ftlb) Oil pump cover screws 7÷9 (5.2÷6.6 ftlb)
Removing the oil sump
- Remove the oil filler plug, the transmission cover,
the complete driving pulley assembly with belt and
sprocket wheel, as described in the Transmission
chapter.
- Drain the oil from the sump as described above.
- Remove the 7 screws, shown in the figure, and
the 2 brackets fixing the rear brake fluid pipe.
- Remove the spring, the by-pass piston, the gas-
ket and the centring dowels shown in the figure.
Inspecting the by-pass valve
- Check the free length of the spring.
- Check that the plunger is not scored.
- Make sure that it slides freely on the crankcase
and that it guarantees a good seal.
- Otherwise, eliminate any impurities or replace
defective parts.
Characteristic
By-pass check: Standard length
54.2 mm
ENG - 141