PIAGGIO MSS ZIP 100 4T, Service Manual

Page: 96 / 192

Refitting the piston rings
- Fit the oil scraper ring starting from the spring,
taking care that the spring ends do not superim-
pose. Fit the two piston rings so that their gaps and
that of the oil scraper ring are never aligned.
- Fit the 2nd sealing ring with the identifying letter
« T » facing towards the piston crown.
- Fit the 1st sealing ring with the reference letter
« T » facing towards the piston crown.
- Misalign the lining openings at 120° as shown in
the figure.
- Lubricate the components with engine oil.
N.B.
IN ORDER TO OBTAIN A GOOD BEDDING, THE 2 SEALING
PISTON RINGS ARE MADE OF CONE SHAPED CONTACT
SECTION TO THE CYLINDER. AS A RESULT IT IS IMPOR-
TANT TO RESPECT THE FITTING INSTRUCTION TO AS-
SEMBLY THE RINGS WITH THE "T" MARK FACING
UPWARDS.
- 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-
Engine
MSS ZIP 100 4T
ENG - 96