Derbi boulevard 125 4t Workshop Manual page 126

Engine
- A wrong installation of a cap can seriously affect
the bushing lubrication pressure.
N.B.
THE MAIN BEARINGS ARE NOT GRINDABLE
Specific tooling
020074Y Support base for checking crankshaft
alignment
Characteristic
Off-line maximum admitted
A = 0.15 mm
B = 0.01 mm
C = 0.01 mm
D = 0.10 mm
Inspecting the crankcase halves
- Before proceeding to check the crankcase
halves, thoroughly clean the all surfaces and oil
ducts.
- On the transmission side crankcase half, take
particular care cleaning the housing and oil ducts
for the following components: the oil pump, the oil
by-pass valve, the main bushings and the cooling
jet on the transmission side (see diagram).
- Take particular care, also, that there are no signs
wear in the oil by-pass valve housing (see Chapter
Lubrication), as this could prevent a good seal in
the valve, which regulates the oil pressure.
N.B.
THE JET IS FED THROUGH THE MAIN BUSH-
INGS. PROPER OPERATION OF THIS COMPO-
NENT IMPROVES THE PISTON TOP COOLING.
CLOGGING HAS EFFECTS THAT ARE DIFFI-
CULT TO DETECT (PISTON TEMPERATURE
INCREASE). FAILURE OR LEAK CAN CONSID-
ERABLY DECREASE THE MAIN BUSHING
AND CONNECTING ROD LUBRICATION PRES-
SURE.
ENG - 126