VESPA 664787 Service Station Manual page 87

Vespa S 50 2T
- Measure the outer diameter of the piston, per-
pendicular to the pin axis.
- Take the measurement in the position shown in
the figure
To classify the cylinder-piston fitting, check the ap-
propriate table
See also
Cylinder - piston assy.
Inspecting the cylinder
- Check that the cylinder does not show seizures.
Otherwise, replace it or adjust it respecting the al-
lowable increases
- Measure the internal diameter of the cylinder with
a bore meter, according to the directions given in
the figure
- Check that the fitting surface with the head is not
dented or distorted.
To classify the cylinder-piston fitting, check the ap-
propriate table
See also
Cylinder - piston assy.
Inspecting the piston rings
- Alternatively insert the two sealing rings in the
cylinder
Using the piston, insert the seals perpendicularly
to the cylinder axis.
- Measure the opening of the sealing rings using a
thickness gauge as shown in the photograph
- If the values are higher than the values prescri-
bed in the chart, substitute the rings
Engine
ENG - 87