PIAGGIO 2005 XEVO 400ie, Руководство по ремонту

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- 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
Inspecting the crankshaft plain bearings
- To obtain a good bushing lubrication it is neces-
sary to have both an optimal lubricating pressure
(4 bar) and a good oil flow rate; the bushings must
be correctly positioned so as not to obstruct the oil
supply channels.
- The main bushings are comprised of two half-
bearings, one with holes and channels for lubrica-
tion whereas the other is solid.
- The solid half-bearing is intended to stand the thrusts caused by combustion, and for this reason it is
arranged opposite the cylinder.
- To prevent obstructions in the oil feeding channels, the matching surface of the two half-bearings must
be perfectly perpendicular to the cylinder axis, as shown in the figure.
- The oil feeding channel section is also affected by the bushings driving depth compared with the
crankshaft axial clearance of the limiting surface.
N.B.
TO KEEP THE BUSHINGS ON THE CRANKCASE IN SUCH POSITION, DRIVING IS FORCED ON
CAST-IRON RINGS INSERTED IN THE CASTING OF BOTH CRANKCASE HALVES.
Engine
XEVO 400ie
ENG - 154