Piston And Gudgeon Pin - APRILIA RSV mille 956X Service And Repair Manual

ENGINE

3.6.31 PISTON AND GUDGEON PIN

Carefully read 0.2.1 (PRECAUTIONS AND GENERAL
INFORMATIONS).
Clean the piston crown (1) and the area above the up-
per piston ring (2) of any residual combustion products.
Check the piston for any cracks and the sliding surface
of the piston for signs of compression (picking-up).
Where necessary, replace the piston.
NOTE
Minor ridging on the piston lining is tolerable.
Measure the piston diameter at a height of 10 mm (3)
across the gudgeon pin axis, using an external microm-
eter.
"Red" piston:
wear limit min. Ø 96.918 mm.
"Green" piston:
wear limit min. Ø 96.930 mm.
Piston play - measurement:
piston play =cylinder diameter minus piston diam-
eter
wear limit max. 0.090 mm.
NOTE
If the wear limit is exceeded, a new piston must
be used or the cylinder replaced, complete with piston.
If the piston is replaced, the two seeger rings securing the
gudgeon pins must always be replaced, along with the
actual gudgeon pins.
Take special care when matching the cylinder - pis-
ton:
"Red" piston - Cylinder "A".
"Green" piston - Cylinder "B".
Use an external micrometer to measure the diameter of
the gudgeon pin hole in the piston in the direction of lift
and the diameter of the gudgeon pin at either end as
well as in the middle.
– Gudgeon pin hole in the direction of lift:
wear limit (4) max. Ø 22.018 mm.
– Gudgeon pin:
wear limit (5) min Ø 21.998 mm.
Check the wear of the gudgeon pin seeger rings with
the bent ends.
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RSV mille