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Inspecting the crankcase halves

- Before proceeding to check the crankcase

halves, thoroughly clean all surfaces and oil ducts.

- For the transmission-side half-crankcase, special

attention should be given to the bushings, to the

cooling jet on the transmission side (see figure)

and to the lubrication duct.

N.B.

THE JET IS FED THROUGH THE MAIN BUSHINGS. PROP-

ER OPERATION OF THIS COMPONENT IMPROVES THE

PISTON TOP COOLING. CLOGGING HAS EFFECTS THAT

ARE DIFFICULT TO DETECT (PISTON TEMPERATURE IN-

CREASE). FAILURE OR LEAK CAN CONSIDERABLY DE-

CREASE THE MAIN BUSHING AND CONNECTING ROD

LUBRICATION PRESSURE.

- For the flywheel side half-crankcase, special at-

tention should be given to the lubrication channels

for the main bearings and to the compartment and

the channels for the oil pump, as well as to the duct

for the by-pass located on the flywheel cover.

N.B.

AS ALREADY DESCRIBED IN THE "LUBRICATION" CHAP-

TER, IT IS ESPECIALLY IMPORTANT THAT THE BY-PASS

HOUSING ON THE FLYWHEEL COVER IS FREE FROM

WEAR THAT MAY IMPAIR THE PROPER SEALING OF THE

LUBRICATION PRESSURE ADJUSTMENT PISTON. THE

HEAD LUBRICATION CHANNEL IS EQUIPPED WITH A

SHUTTER JET; THIS GIVES A "LOW PRESSURE" HEAD

LUBRICATION. THIS CHOICE WAS MADE TO REDUCE

THE OIL TEMPERATURE IN THE SUMP.

The jet clogging impairs the head lubrication and the timing mechanisms.

A jet failure causes a decrease in the main bearing and connecting rod lubrication pressure.

- Check that the surfaces exhibit no dents or deformations, with special attention to the crankcase

coupling and the crankcase-cylinder surfaces.

- Any defects in the crankcase gasket or matching surfaces (see Flywheel cover coupling) can cause

pressurised oil leaks, thereby affecting the connecting rod and main bearing lubrication pressure.

- Check the main bearing seats that limit axial clearance in the crankshaft exhibit no wear. For the

dimensional check, refer to the instructions about checking the axial clearance and the dimensions on

the crankshaft

Beverly 500 i.e. Engine

ENG - 145

PIAGGIO BV 500 USA User Manual

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