APRILIA SPORTCITY CUBE 250 2010 Service Station Manual page 20

Characteristics
THE PISTON MUST BE FITTED WITH THE ARROW FACING TOWARDS THE EXHAUST SIDE, THE
PISTON RINGS MUST BE FITTED WITH THE REFERENCE «TOP» OR THE STAMPED MARK
FACING UPWARDS.
- Check the pin outside diameter
- Calculate the rod small end - gudgeon pin cou-
pling clearance.
Characteristic
Pin diameter: Standard clearance
0.015 ÷ 0.029 mm
Pin diameter: Standard diameter
14.996 ÷ 15.000 mm
Piston check
- Measure the diameter of the bearings on the pis-
ton.
Characteristic
Standard diameter
15+0.006 +0.001 mm
- Calculate the pin - piston coupling clearance.
NOTE
THE PIN HOUSINGS HAVE TWO LUBRICATION CHANNELS FOR THIS REASON MEASURE THE
DIAMETER ACCORDING TO THE PISTON AXIS
Characteristic
Standard clearance:
0.001 ÷ 0.010 mm
- Carefully clean the sealing rings housings.
- Measure the sealing rings - pistons coupling
clearance using suitable sensors, as shown in the
diagram
- If clearances measured exceed the limits speci-
fied in the table below, the piston should be re-
placed by a new one.
NOTE
MEASURE CLEARANCE BY INSERTING THE BLADE OF
THE FEELER GAUGE FROM THE 2nd SEALING RING
SIDE.
Fitting clearance
1st compression ring - standard coupling
clearance
0.015 ÷ 0.06 mm
maximum clearance allowed after use
2nd compression ring - standard coupling
CHAR - 20
1st compression ring -
0.07 mm
SPORTCITY CUBE 250 - 300