APRILIA RSV mille 956X Service And Repair Manual page 162

RSV mille
Use a feeler gauge to measure the end play (7-8-9) of
the piston rings inside the grooves.
– L-section ring
wear limit (7) max. 0.12 mm;
– Tapered protruding ring:
wear limit (8) max. 0.12 mm;
– Scraper ring
wear limit (9) max. 0.10 mm.
a
CAUTION
The piston rings are fragile.
Carefully remove the piston rings from the piston.
NOTE
The piston ring groove can be cleaned using a
scraper or an old piston ring.
Clean the piston ring grooves and the oil return holes
(10) in the scraper ring groove, then blow a jet of com-
pressed air inside.
Check the scraper ring (11), the tapered protruding ring
(12) and the L-section ring (13) to make sure the sliding
surface is cleaned.
Measure the piston ring gap (14) with a feeler gauge.
wear limit max. 1.00 mm.
NOTE
In order to measure the gap required, insert the
piston ring in the cylinder and push it inside so that it is
lined up with the piston.
The cylinder bore must not feature any signs of wear.
Measure the thickness of the rings with a micrometer.
– L-section ring:
wear limit (15) min. 0.85 mm;
– Tapered protruding ring:
wear limit (16) min. 1.20 mm;
– Scraper ring:
wear limit (17) min. 2.45 mm.
Fit the scraper ring (11), the tapered protruding ring
(12) and the L-section ring (13) from the bottom up; the
word "TOP" on the rings must face up.
NOTE
Rotate the piston rings so that the three gaps
are staggered by approx. 120°.
ENGINE
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