Yamaha F30B 2018, Service Manual

Page: 257 / 348

8-37
S himming
3. Select:
• Reverse gear shim (T2)
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Determine the reverse gear shim (T2)
thickness adjustment using the “Reverse
gear shim (T2) selection chart” according
to the backlash measurement (BL2) from
“Measuring the reverse gear backlash”.
See “Reverse gear shim (T2) selection
chart” (A-19).
TIP:
• If the shim thickness adjustment value is pos-
itive, increase the current shim thickness by
that amount and, if the value is negative, de-
crease the current shim thickness by that
amount.
• The gray-colored area on the selection chart
indicates the range of the specified backlash.
Shimming is not required if the measured
backlash is within the gray-colored area.
• The values for the shim thickness adjust-
ments specified in the selection chart are in-
tended to obtain the median value within the
range for the specified forward gear or re-
verse gear backlash.
• The table that follows the selection chart
shows the shim thickness adjustments for the
points marked on the chart.
Example:
Backlash measurement (BL2) = 0.20 mm
“a”
Reverse gear shim (T2) thickness adjust-
ment = –0.42 mm “b”
The current shim thickness must be de-
creased by 0.42 mm.
b. Calculate the new reverse gear shim (T2)
thickness.
TIP:
• Use the lowest number of shims to obtain the
required shim thickness.
• If the calculated shim thickness cannot be ob-
tained with a combination of the available
shims, increase or decrease the shim thick-
ness by 0.01 mm.
Calculation formula:
New reverse gear shim (T2) thickness =
Current reverse gear shim thi
shim thickness adjustment
Example:
Use the following formula when the shim
thickness adjustment value is positive.
Current reverse gear shim thickness =
1.00 mm
Shim thickness adjustment = 0.17 mm
New reverse gear shim (T2) thickness =
1.00 mm + 0.17 mm = 1.17 mm
Use the following formula when the shim
thickness adjustment value is negative.
Current reverse gear shim thickness =
1.00 mm
Shim thickness adjustment = –0.42 mm
New reverse gear shim (T2) thickness =
1.00 mm + (–0.42 mm) = 0.58 mm
A. Backlash measurement (BL2)
B. Shim thickness adjustment
0 5 10 15 20 25 30 35 A
B –0.53 –0.50 –0.47 –0.45 –0.42 –0.39 –0.37 –0.3
–0.10
–0.20
–0.30
–0.40
–0.50
–0.60
–0.70
–0.
8 0
0 5 10 15 20 25 30 35
B
(mm)
A (1/100 mm)
a
b