- Measure the outside diameter of the piston, per-
pendicular to the gudgeon pin axis.
- Measure 36.5 mm from the piston crown's shown
in the figure.
N.B.
THE PIN HOUSINGS HAVE 2 LUBRICATION CHANNELS.
FOR THIS REASON MEASUREMENT OF THE DIAMETER
MUST BE CARRIED OUT ACCORDING TO THE AXIS OF
THE PISTON.
- Using a bore meter, measure the inner cylinder
diameter at three different points according to the
directions shown in the figure.
- Check that the coupling surface with the head is
not worn or misshapen.
- Pistons and cylinders are classified into catego-
ries based on their diameter. The coupling is car-
ried out in pairs (A-A, B-B, C-C, D-D).
Characteristic
Maximum allowable run-out:
0.05 mm
- The cylinder rectifying operation should be car-
ried out with a surfacing that respects the original
angle.
- The cylinder surface roughness should be 0.9
micron.
- This is indispensable for a good seating of the
sealing rings, which in turn minimises oil consump-
tion and guarantees optimum performance.
- The pistons are oversized due to cylinder rectifi-
cation and are subdivided into three categories
1st, 2nd, 3rd with 0.2-0.4-0.6 mm oversize. They
are also classified into 4 categories A-A, B-B, C-
C, D-D.
Inspecting the piston
- Carefully clean the sealing ring housings.
- Measure the coupling clearance between the sealing rings and the piston grooves using suitable
sensors, as shown in the diagram.
- If the clearance is greater than that indicated in the table, replace the piston.
Vespa LX 125 - 150 i.e.
Engine
ENG - 117
Summary of Contents for LX Series
Page 4: ......
Page 6: ...INDEX OF TOPICS CHARACTERISTICS CHAR ...
Page 21: ...INDEX OF TOPICS TOOLING TOOL ...
Page 33: ...INDEX OF TOPICS MAINTENANCE MAIN ...
Page 44: ...INDEX OF TOPICS TROUBLESHOOTING TROUBL ...
Page 48: ...Troubleshooting Vespa LX 125 150 i e TROUBL 48 ...
Page 49: ...INDEX OF TOPICS ELECTRICAL SYSTEM ELE SYS ...
Page 52: ...Components arrangement Electrical system Vespa LX 125 150 i e ELE SYS 52 ...
Page 86: ...INDEX OF TOPICS ENGINE FROM VEHICLE ENG VE ...
Page 90: ...Engine from vehicle Vespa LX 125 150 i e ENG VE 90 ...
Page 91: ...INDEX OF TOPICS ENGINE ENG ...
Page 137: ...Conceptual diagrams Vespa LX 125 150 i e Engine ENG 137 ...
Page 146: ...INDEX OF TOPICS INJECTION INJEC ...
Page 164: ...Injection Vespa LX 125 150 i e INJEC 164 ...
Page 171: ...Vespa LX 125 150 i e Injection INJEC 171 ...
Page 185: ...INDEX OF TOPICS SUSPENSIONS SUSP ...
Page 205: ...INDEX OF TOPICS BRAKING SYSTEM BRAK SYS ...
Page 214: ...INDEX OF TOPICS CHASSIS CHAS ...
Page 222: ...INDEX OF TOPICS PRE DELIVERY PRE DE ...
Page 226: ...INDEX OF TOPICS TIME TIME ...
Page 272: ...T Tank 256 Transmission 9 46 92 103 113 241 Turn indicators 65 Tyres 13 V Vehicle 8 87 88 ...