Yamaha F115A - Checking the Cylinder Block; Checking the Piston

5-38
POWR
E
CRANKSHAFT AND PISTON/
CONNECTING ROD ASSEMBLY
CHECKING THE CYLINDER BLOCK 5
Measure:
• Cylinder bore
Out of specification → Rebore the cyl-
inder or replace the cylinder block.
NOTE:
Measure the cylinder bore in parallel and at
a right angle to the crankshaft. Then, aver-
age the measurements.
Standard
Wear
limit
Cylinder
bore “D”
79.000 - 79.020 mm
(3.110 - 3.111 in)
—
Taper limit
“T”
—
0.08 mm
(0.003 in)
Out of
round limit
—
0.08 mm
(0.003 in)
D = Maximum Dia. (D
1 - D6)
T = (maximum D
1 or D2) – (minimum D5
or D6)
20 mm (0.8 in)
D1 and D2
D3 and D4
D5 and D6
70 mm (2.8 in)
120 mm (4.7 in)
D1
D2
D
5460
CHECKING THE PISTON 5
Measure:
• Piston diameter
Out of specification → Replace the pis-
ton.
Distance
a
Piston diameter
Standard
13 mm
(0.51 in)
78.928 - 78.949 mm
(3.1074 - 3.1082 in)
Oversize piston diameter
Oversize 1: + 0.25 mm (0.001 in)
a
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