VESPA 946 E4 EMEA 2021 Manual page 171

Vespa 946 E4-E5 EMEA-USA-ASIA (2021-)
- By means of the table, see the Specifications chapter identify the cylinder base gasket thickness to
be used for refitting. Correctly identify the cylinder base gasket thickness to keep the correct compres-
sion ratio.
- Remove the special tool and the cylinder.
See also
Slot packing system
Refitting the piston rings
- Pistons (like cylinders) are supplied in 4 catego-
ries: A, B, C and D, and must be fitted so that the
reference arrow faces the exhaust duct. The letter
is found at the centre of the piston.
- Fit the sealing rings with the word TOP or the
identification letter facing upwards. In any case,
the step must be facing opposite the piston crown.
- Sealing rings are manufactured with a cylinder
contact conical cross-section and piston gaps
must be offset by 120° in order to obtain a better
bedding.
- Lubricate rings with engine oil when fitting them.
CAUTION
AT EVERY NEW MOUNTING USE RETAINER RING PINS.
Engine
ENG - 171