APRILIA SCARABEO 500 2008 Service Station Manual page 179

SCARABEO 500
NOTE
IF DEVIATIONS (PROTRUSIONS OR RECESSES) CLOSE TO THE CHANGE OF CATEGORY ARE
MEASURED, REPEAT THE MEASUREMENT AT THE OPPOSITE SIDE. TO DO SO, REPEAT THE
TOOL FITTING OPERATION, INVERTING ITS POSITION.
Characteristic
Recess / Protrusion measured 1
- 0.185 ÷ - 0.10
Gasket thickness 1
0.4 ± 0.05
Recess / Protrusion measured 2
- 0.10 ÷ + 0.10
Gasket thickness 2
0.6 ± 0.05
Recess / Protrusion measured 3
+ 0.10 ÷ + 0.185
Gasket thickness 3
0.8 ± 0.05
Refitting the piston rings
- Place the oil scraper ring spring on the piston.
- Fit the oil scraper ring keeping the gap opposed
to the spring union and the word "top" facing the
piston crown. In any case, the chamfered side of
the must be facing the piston crown.
- Fit the middle piston ring with the identification
letter or the word "top" facing the piston crown. In
any case, the tapered side of the ring must be fac-
ing opposite the piston crown.
- Fit the top compression ring in the direction
forced by the housing.
- It is advisable to use a fitter to help fitting the
rings.
NOTE
THE 2 PISTON RINGS ARE MADE WITH A TA-
PERED CYLINDRICAL CONTACT SECTION.
THIS IS TO OBTAIN A BETTER BEDDING.
- Offset the piston ring openings by 120º as shown in the figure.
- Lubricate the components with engine oil.
- The engine is fitted with a top ring with an L-shaped section.
Engine
ENG - 179