Yamaha F20A Service Manual page 270

LOWR
SHIMMING
Base plate 3:
YB-07003
Dial gauge 4:
YU-03097/90890-01252
Flexible stand 5:
YU-34481/90890-06705
Slowly turn the drive shaft clockwise
and counterclockwise. When the drive
shaft stops in each direction, measure
the backlash.
2. Adjust:
Reverse gear backlash
Remove or add shim(s).
Reverse gear
backlash
Less than
0.93 mm (0.037 in)
More than
1.65 mm (0.065 in)
Available shim thickness:
1.0, 1.1, 1.2, and 1.3 mm
6-33
E
Shim thickness
To be decreased
by (1.29 – M) × 0.49
To be increased by
(M – 1.29) × 0.49