Yamaha F40BED, Service Manual, Page: 228 / 537

CYLINDER HEAD
5-30
E
POWR
CHECKING OIL PUMP
Measure:
• Clearance
• Clearance
• Clearance
Out of specification
→
Replace.
CHECKING THE CYLINDER HEAD
1. Measure:
• Cylinder head warpage
Out of specification
→
Reface.
Resurfacing steps
(1) Place a 400 - 600 grit wet sandpaper on
the surface plate.
(2) Resurface the cylinder head using a fig-
ure-eight sanding pattern.
NOTE:
To ensure an even surface, rotate the cylin-
der head several times.
2. Measure:
• Valve guide bore
Out of specification
→
Replace the
guide.
b
c
a
Clearance
0.03 - 0.15 mm
(0.001 - 0.006 in)
0 - 0.12 mm (0 - 0.005 in)
0.03 - 0.08 mm
(0.001 - 0.003 in)
a
b
c
a
b
c
Warpage limit
0.1 mm (0.004 in)
a
Valve guide bore limit
5.500 - 5.512 mm
(0.2165 - 0.2170 in)
a