Yamaha F20A, Service Manual

Page: 198 / 444

5-41
POWR
E
CRANKCASE, CRANKSHAFT ASSY., AND CYLINDER
BODY
Connecting rod color code
indicator
a
:
A: Blue
B: Black
C: Brown
Bearing color code
b
:
A: Blue
B: Black
C: Brown
NOTE:
●
Make sure the “Y” mark on the connect-
ing rod faces towards the flywheel side
of the crankshaft.
●
Do not move the crankshaft until the
big-end oil clearance measurement has
been completed.
Piston ring installation
1. Install:
●
Oil ring 1
●
2nd piston ring 2
●
Top piston ring 3
CAUTION:
●
Do not scratch the piston or break the pis-
ton rings.
●
After installing the piston rings, check
that they move smoothly.
NOTE:
●
Offset the piston-ring end gaps as shown.
a
Oil ring side rail
b
Oil ring expander
c
2nd piston ring
d
Top piston ring
●
Piston rings should be replaced as a set.
Å
20
±
5 mm (0.79
±
0.2 in)
ı
120˚
±
15˚
Piston installation
1. Install:
●
Piston
Piston slider:
YU-33294/90890-06529
a
c
d
a
b
Å
ı ı
Å
UP