APRILIA Atlantic 300 Service Station Manual page 20

Characteristics
- 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
clearance
0.015 ÷ 0.06 mm
maximum clearance allowed after use
oil scraper - standard coupling clearance
oil scraper - maximum clearance al-
÷ 0.06 mm
lowed after use
0.07 mm
- Check that the coupling surface with the head is
not worn or misshapen.
- Pistons and cylinders are classified according to
their diameter. The coupling is carried out in pairs
(M-M, N-N, O-O, P-P).
Characteristic
Maximum run-out allowed:
0.05 mm
Crankcase - crankshaft - connecting rod
CRANKSHAFT
CHAR - 20
1st compression ring -
0.07 mm
2nd compression ring -
0.07 mm
0.015
ATLANTIC 300 i.e.