Checking The Piston; Fitting The Piston - APRILIA RS4 50 2011 Workshop Manual

Engine
Specification
Nominal cylinder diameter (D)
Piston diameter (D)
Piston nominal diameter (D)
Cylinder diameter (D)
CAUTION
COUPLING CLEARANCE IN THE FITTING:
0.045 - 0.055 mm (0.0017716 - 0.0021653 in)

Checking the piston

- Check the piston outside diameter following the
perpendicular axis to the pin seat. Carry out meas-
urements 15 mm (0.59 in) away from the lowest
circlip seat
Characteristic
Serviceability limit:
0.05 mm (0.0019 in)

Fitting the piston

- Refit the piston sealing circlips
- Fit a new cylinder base gasket
- Refit the roller cage at the connecting rod small
end and make sure to lubricate the components
with recommended oil
- Refit the piston paying attention to the direction
of the arrow indicated at the piston crown. This ar-
row should be facing the outlet
- Fully fit the previously lubricated pin and mount
two new pin retaining seeger rings being careful to
fit them in their correct positions
- Lubricate both the cylinder and the piston faying
surfaces and the sealing circlips
- Carefully fit the piston in the cylinder being careful
to press the sealing circlips in their positions
ENG - 120
CLASS D
39.905 mm (1.57106 in)
39.8525 - 39.8575 mm (1.568991 - 1.569188 in)
39.855 mm (1.56909 in)
39.9025 - 39.9075 (1.57096 - 1.571157 in)
RS4 50 MY2011
Desc./Quantity