Yamaha F30A 2018, Service Manual

Page: 183 / 348

7-28
Cylinder head
Checking the cylinder head bolt
1. Measure:
• Cylinder head bolt (M9) diameter
Out of specification

Replace.
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a. Measure the diameters “a” and “b” of the
cylinder head bolt (M9) at the specified
measuring points “c” and “d”.
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Installing the cylinder head
Before installing the cylinder head, check the
cylinder head bolts. See “Checking the cylinder
head bolt” (7-28).
1. Check that the hole “a” on the retaining
plate is aligned with the “
△
” mark “b” on
the cylinder block.
2. Install:
• Dowel pin
• Cylinder head gasket
• Cylinder head
3. Tighten:
• Cylinder head bolt (M9)
• Cylinder head bolt (M6)
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a. Tighten the cylinder head bolts (M9) “1” to
the specified torques in 3 stages and in the
order [1], [2], and so on.
TIP:
In the third tightening stage for the cylinder
head bolts (M9) “1”, mark the bolts and cylinder
head with identification marks “a”, and then
tighten the bolts 90

from the marks on the cyl-
inder head.
b. Tighten the cylinder head bolts (M6) “2” to
the specified torques in 2 stages and in the
order [9], [10], and so on.
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Cylinder head bolt (M9) diameter
difference limit
“a” – “b” = Less than 0.13 mm
(0.01 in)
Measuring point “c”: 10.0 mm
(0.39 in)
Measuring point “d”: 62.5 mm
(2.46 in)
d
b a
c
b
a
Cylinder head bolt (M9) “1” [1]–[8]
1st: 17 N·m (1.7 kgf·m, 13 lb·ft)
2nd: 34 N·m (3.4 kgf·m, 25 lb·ft)
3rd: 90

Cylinder head bolt (M6) “2” [9]–
[12]
1st: 6 N·m (0.6 kgf·m, 4.4 lb·ft)
2nd: 12 N·m (1.2 kgf·m, 8.9 lb·ft)
New
90°
[7]
[3]
[12]
[10]
[9]
[11]
[8]
[4]
[1]
[5]
[2]
[6]
1
2
a
T
R
.
.