TOHATSU BFT250A Service Manual page 542

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GEAR CASE (COUNTER ROTATION)
HOW TO SELECT SHIM COMBINATION
To obtain 0.90 mm (0.035 in) of shim thickness,
combine one gear shim A, one gear shim C, and one
gear shim D, or combine four gear shim A and one gear
shim D.
FORWARD BEVEL GEAR SHIM
Remove the gear case cover from the gear case (page
17-7).
Cross reference the engagement mark [1] located on
the gear case cover installation part of the gear case [2]
and the tolerance calculated in the previous step, and
refer to the forward bevel gear shim selection table to
determine the required thickness of the shim (Sf).
Forward bevel gear shim selection table
Gear case
engagement
mark
Select the shims from the forward bevel gear shims of
different thickness to obtain the required thickness (Sf)
by combining the shims.
Shim type table
Install the gear case cover on the gear case (page 17-
7).
After shim selection, inspect the forward bevel gear
backlash (page 17-40)
REVERSE BEVEL GEAR SHIM
Measure the bearing height (H) of a new ball bearing
(55 x 100 x 21 mm) [1] using a regular vernier caliper [2]
as shown, and record the measurement.
Calculate the tolerance using the measurement H
obtained in the previous step and the following formula.
Formula: Tolerance = H – 21.5
Example:
When measurement (H) is 21.45 mm (0.844 in):
Tolerance = 21.45 – 21.5 = –0.05
The tolerance is –0.05 mm (–0.002 in).
17-38
Thickness
A
B
C
D
E
F
Shim type Thickness
Shim A
Shim B
Shim C
Shim D
Unit: mm
0.10
0.15
0.20
0.25
0.30
0.35
0.10 mm
0.15 mm
0.30 mm
0.50 mm
[2]
[1]
[1]
[2]