PGO BR-500, Service Manual

Page: 131 / 330

The jet clogging impairs the head lubricationand the timing mechanisms.
A jet failure causes a decrease of the benchbrass and connecting rod lubrication pressure.
- Check that the surfaces are free from dents ordeformations, with special attention to the crankcase coupling and
thecrankcase-cylinder surfaces.
- Any defects in the crankcase gasket ormatching surfaces (see Flywheel cover coupling) can cause pressurised
oilleaks, thereby affecting the connecting rod and bench brass lubricationpressure.
- Check that the driving shaft axial clearancecontainment surfaces are free from wear. For the dimensional check,
- Before checking the
crankcase, carefully clean all
lubrication channels and
surfaces.
- For the transmission-side
half-crankcase, special
attention should be given to
the brasses, to the cooling jet
on the transmission side (see
figure) and to the lubrication
duct.
N.B.:
The jet is fed through
the bench brasses. Proper
operation of this component
improves the piston top
cooling. Clogging has effects
that are difficult to detect
(piston temperature increase).
Failure or leak can
considerably decrease the
bench brass and connecting
rod lubrication pressure.
- For the flywheel side half-
crankcase, special attention
should be given to the
lubrication channels for the
bench brasses 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" chapter, 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 provided
with a shutter jet; this gives a
"low pressure" head
lubrication. This choice was
made to reduce the oil
temperature in the sump.
PGO BR-500 ENGINE
refer tothe instructions relating to the axial clearance and dimensions check on thedriving shaft
P.10-112
Crankcase & Driving shaft