Service Points; Cylinder Body Inspection - Yamaha 40V Service Manual

POWR
CRANKCASE AND CYLINDER BODY

SERVICE POINTS

Cylinder body inspection

1. Inspect:
Water jacket
Material deposit/Corrosion → Clean.
Cylinder inner surface
Score marks → Clean.
Use #600 ~ 800 grit wet sandpaper.
NOTE:
Do not scratch the fitting surfaces of the
crank case and cylinder head.
2. Inspect:
Exhaust wall
Crack/Damage → Replace.
Carbon deposit → Clean.
Use a round scraper.
NOTE:
Do not scratch the fitting surfaces of the cyl-
inder and exhaust cover.
3. Measure:
Cylinder bore "D"
Use cylinder gauge.
Out of specification → Rebore or
replace.
NOTE:
Measure the cylinder bore "D" in parallel.
Then, find the average of the measurement.
Cylinder 67.00 ~ 67.02 mm
bore "D" (2.638 ~ 2.639 in)
Taper
limit T:
Out of
round limit
D = Maximum Dia. (D
T = (maximum D
or D )
6
A: 10 mm (0.4 in) below the cylinder top
B: 5 mm (0.2 in) above the exhaust port
C: 5 mm (0.2 in) below the scavenging port
5-29
Standard Wear limit
67.10 mm
(2.642 in)
0.08 mm
—
(0.003 in)
0.05 mm
—
(0.002 in)
– D )
1 6
or D ) – (minimum D
1 2
E
5