- Check the main bearing seats that limit axial
clearance in the crankshaft show no signs of wear.
The dimension between these seats is measured
by way of the procedure described previously for
measuring the crankshaft axial clearance and di-
mensions.
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 shutters in the oil feeding channels,
the matching surface of the two half-bearings must
be perfectly orthogonal 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 THIS POSITION OF THE BUSHINGS ON THE
CRANKCASE, FITTING IS FORCED ON STEEL RINGS IN-
SERTED IN THE CASTING OF BOTH CRANKCASE
HALVES.
Characteristic
Standard driving depth
1.35 - 1.6
- Check the inside diameter of the main bushings in the three directions indicated in the diagram.
- Repeat the measurements for the other bushing half. see diagram.
- The standard bushing diameter after driving is variable on the basis of a coupling selection.
Vespa LX 125 - 150 4T Euro 3
Engine
ENG - 117
Summary of Contents for LX 125 4T Euro 3
Page 1: ...SERVICE STATION MANUAL 633977 EN Vespa LX 125 150 4T Euro 3 ...
Page 4: ......
Page 6: ...INDEX OF TOPICS CHARACTERISTICS CHAR ...
Page 19: ...INDEX OF TOPICS TOOLING TOOL ...
Page 29: ...INDEX OF TOPICS MAINTENANCE MAIN ...
Page 34: ...INDEX OF TOPICS TROUBLESHOOTING TROUBL ...
Page 40: ...INDEX OF TOPICS ELECTRICAL SYSTEM ELE SYS ...
Page 69: ...INDEX OF TOPICS ENGINE FROM VEHICLE ENG VE ...
Page 73: ...INDEX OF TOPICS ENGINE ENG ...
Page 120: ...Conceptual diagrams Engine Vespa LX 125 150 4T Euro 3 ENG 120 ...
Page 145: ...INDEX OF TOPICS SUSPENSIONS SUSP ...
Page 160: ...INDEX OF TOPICS BRAKING SYSTEM BRAK SYS ...
Page 171: ...INDEX OF TOPICS CHASSIS CHAS ...