Cylinder Inspection; Piston Inspection; Service Points - Yamaha F20A Service Manual

POWR
CRANKCASE, CRANKSHAFT ASSY., AND
CYLINDER BODY

SERVICE POINTS

Cylinder inspection

1. Measure:
Cylinder bore
Out of specification → Rebore or
replace the cylinder.
NOTE:
Measure the cylinder bore in parallel and at
a right angle to the crankshaft. Then, aver-
age the measurements.
65.000 ~ 65.015 mm
Cylinder
(2.5590 ~ 2.5596 in)
bore "D"
Taper
limit "T"
Out of
round limit
D = Maximum Dia. (D
T = (maximum D
or D )
6

Piston inspection

1. Measure:
Piston diameter
Out of specification → Replace the
piston.
Distance
2 mm
Standard
(0.07 in)
Oversize piston diameter:
Oversize 1: + 0.25 mm (0.001 in)
(except for USA)
Oversize 2: + 0.50 mm (0.002 in)
5-36
Standard
0.08 mm
—
(0.003 in)
0.08 mm
—
(0.003 in)
~ D )
1 6
or D ) – (minimum D
1 2
Piston diameter
a
64.950 ~ 64.965 mm
(2.5570 ~ 2.5573 in)
E
Wear
limit
—
5