Yamaha F225A, Руководство по обслуживанию

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69J3D11
5-48
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9
Checking the cylinder bore
1. Measure the cylinder bore (D
1
–D
6
) at
measuring points
a
,
b
, and
c
, and in
direction
d
(D
1
, D
3
, D
5
), which is parallel
to the crankshaft, and direction
e
(D
2
,
D
4
, D
6
), which is at a right angle to the
crankshaft.
a
20 mm (0.8 in)
b
60 mm (2.4 in)
c
100 mm (3.9 in)
2. Calculate the taper limit. Replace or
rebore the cylinder block if out of specifi-
cation.
3. Calculate the out-of-round limit. Replace
or rebore the cylinder block if out of spec-
ification.
Checking the piston clearance
1. Rebore the cylinder or replace the piston
and piston rings as a set, or the cylinder
block, or all parts if out of specification.
Checking the piston rings
1. Check the piston ring dimensions of B
and T. Replace if out of specification.
2. Level the piston ring
1
in the cylinder
with a piston crown.
3. Check the piston ring end gap
d
at the
specified measuring point. Replace if out
of specification.
Piston diameter
a
:
93.921–93.941 mm
(3.6977–3.6985 in)
Measuring point
b
:
5 mm (0.2 in) up from the bottom of
the piston skirt
Cylinder bore (D
1
–D
6
):
94.00–94.02 mm
(3.7008–3.7016 in)
Taper limit:
D
1
–D
5
(direction
d
)
D
2
–D
6
(direction
e
)
0.05 mm (0.0020 in)
Out-of-round limit:
D
2
–D
1
(measuring point
a
)
D
6
–D
5
(measuring point
c
)
0.01 mm (0.0004 in)
S69J5B70
D
1
D
2
D
3
D
4
D
5
D
6
Piston clearance:
0.075–0.080 mm
(0.0029–0.0031 in)
Piston ring dimensions:
Top ring
a
:
B: 1.17–1.19 mm
(0.0461–0.0468 in)
T: 2.8–3.0 mm (0.110–0.118 in)
Second ring
b
:
B: 1.17–1.19 mm
(0.0461–0.0468 in)
T: 3.6–3.8 mm (0.142–0.150 in)
Oil ring
c
:
B: 2.40–2.47 mm
(0.0945–0.0972 in)
T: 2.3–2.7 mm (0.091–0.106 in)
Cylinder block