Inspecting the cylinder
- Using a bore meter, measure the inner cylinder
diameter at three different points according to the
directions shown in the figure.
- Check that the head coupling surface is not worn
or misshapen.
- Pistons and cylinders are classified according to
diameter. The coupling must be made with those
of the same type (M-M, N-N, O-O, P-P).
Characteristic
cylinder: standard diameter
71.990 - 72.018 mm (at 33 mm)
Maximum allowable run-out:
0.05 mm
Inspecting the piston rings
Sealing rings
- Alternately insert the three sealing rings into the
cylinder, in the area where it retains its original di-
ameter. Using the piston, insert the rings perpen-
dicularly to the cylinder axis.
- Measure the opening (see figure) of the sealing
rings using a feeler gauge.
- If any measurements are greater than specified,
replace the piston rings.
N.B.
BEFORE REPLACING ONLY THE PISTON
RINGS, ENSURE THAT THE CLEARANCE BE-
TWEEN THE PISTON RINGS AND THE PISTON
RING GROOVES, AND BETWEEN THE PISTON
AND THE CYLINDER, IS AS SPECIFIED. IN ANY
CASE, NEW PISTON RINGS USED IN COMBI-
NATION WITH A USED CYLINDER MAY HAVE
DIFFERENT BEDDING CONDITIONS THAN
THE STANDARD.
Characteristic
Top piston ring
Standard opening: 0.15 ÷ 0.30 mm
Middle piston ring
Standard opening: 0.20 ÷ 0.40 mm
Vespa GTV 250 i.e.
Engine
ENG - 35
Summary of Contents for 633844 IT
Page 4: ......
Page 6: ......
Page 7: ...INDEX OF TOPICS CHARACTERISTICS CHAR ...
Page 21: ...INDEX OF TOPICS TOOLING TOOL ...
Page 34: ...Tooling Vespa GTV 250 i e TOOL 14 ...
Page 35: ...INDEX OF TOPICS MAINTENANCE MAIN ...
Page 48: ...Maintenance Vespa GTV 250 i e MAIN 14 ...
Page 49: ...INDEX OF TOPICS TROUBLESHOOTING TROUBL ...
Page 53: ...INDEX OF TOPICS ELECTRICAL SYSTEM ELE SYS ...
Page 86: ...Electrical system Vespa GTV 250 i e ELE SYS 34 ...
Page 87: ...INDEX OF TOPICS ENGINE FROM VEHICLE ENG VE ...
Page 94: ...Engine from vehicle Vespa GTV 250 i e ENG VE 8 ...
Page 95: ...INDEX OF TOPICS ENGINE ENG ...
Page 152: ...Conceptual diagrams LUBRICATION CIRCUIT Engine Vespa GTV 250 i e ENG 58 ...
Page 153: ...Vespa GTV 250 i e Engine ENG 59 ...
Page 161: ...INDEX OF TOPICS INJECTION INJEC ...
Page 178: ... REMOTE CONTROLS CONTROL UNIT FUSES ETC Injection Vespa GTV 250 i e INJEC 18 ...
Page 182: ...Remove the filter from the pump support Injection Vespa GTV 250 i e INJEC 22 ...
Page 194: ...Injection Vespa GTV 250 i e INJEC 34 ...
Page 203: ...SIGNAL CONTROL Vespa GTV 250 i e Injection INJEC 43 ...
Page 206: ...Injection Vespa GTV 250 i e INJEC 46 ...
Page 207: ...INDEX OF TOPICS SUSPENSIONS SUSP ...
Page 228: ...Suspensions Vespa GTV 250 i e SUSP 22 ...
Page 229: ...INDEX OF TOPICS BRAKING SYSTEM BRAK SYS ...
Page 245: ...INDEX OF TOPICS COOLING SYSTEM COOL SYS ...
Page 248: ...Cooling system Vespa GTV 250 i e COOL SYS 4 ...
Page 249: ...INDEX OF TOPICS CHASSIS CHAS ...
Page 262: ...Chassis Vespa GTV 250 i e CHAS 14 ...
Page 263: ...INDEX OF TOPICS PRE DELIVERY PRE DE ...
Page 267: ...INDEX OF TOPICS TIME TIME ...