VESPA LX 4T USA Workshop Manual page 91

LX 4T USA
Refitting the piston 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 thickness 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.
SEALING RINGS
Name Descripti Dimensio
on
Top piston
ring 0.20 mm
Middle pis-
ton ring 0.20 mm
oil scraper
0.70 mm
Initials Quantity
ns
0.08 ÷ 0.35 mm
0.05 ÷ 0.30 mm
0.20 ÷ 0.80 mm
Engine
ENG - 91