Checking The Piston Pin; Installing The Piston - Yamaha 5KM2-AE1 Service Manual

CYLINDER AND PISTON

CHECKING THE PISTON PIN

1.Check:
Piston pin
G
Blue discoloration/grooves → Replace, then
inspect the lubrication system.
2.Measure:
Piston pin-to-piston clearance
G
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Measurement steps:
Measure the piston pin outside diameter a.
G
If out of specification, replace the piston pin.
Outside diameter (piston pin):
21.991 ~ 22.000 mm
(0.8658 ~ 0.8661 in)
<Limit>: 21.971 mm (0.8650 in)
Measure the piston inside diameter b.
G
Piston pin bore inside diameter:
22.004 ~ 22.015 mm
(0.8663 ~ 0.8667 in)
<Limit>: 22.045 mm (0.8679 in)
G
Calculate the piston pin-to-piston clearance
with the following formula.
Piston pin-to-piston clearance =
Bore size (piston pin) b –
Outside diameter (piston pin) a
G
If out of specification, replace the piston.
Piston pin-to-piston clearance:
0.004 ~ 0.024 mm
(0.00016 ~ 0.00094 in)
<Limit>: 0.07 mm (0.003 in)
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INSTALLING THE PISTON

1.Install:
Piston rings
G
(onto the piston)
NOTE:
Be sure to install the piston rings so that the
G
manufacturer's
located on the upper side of the rings.
Lubricate the piston and piston rings liberally
G
with engine oil.
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