Yamaha F150A Service Manual page 349

2. Measure the thickness of original forward
gear shim (T1) in 2 places.
TIP:
Do not reuse a shim if deformed or
scratched.
3. Determine the forward gear shim (T1)
thickness adjustment using the "Forward
gear shim (T1) selection chart" according
to the backlash measurement (BL1) from
"Measuring the forward gear backlash".
See "Forward gear shim (T1) selection
chart (F150A)" (A-13) or "Forward gear
shim (T1) selection chart (F150B)" (A-
14).
TIP:
• If the shim thickness adjustment value is
positive, increase the current shim thick-
ness by that amount and, if the value is
negative, decrease the current shim thick-
ness 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-col-
ored area.
• The values for the shim thickness adjust-
ments specified in the selection chart are
intended to obtain the median value within
the range for the specified forward gear or
reverse gear backlash.
• The table that follows the selection chart
shows the shim thickness adjustments for
the points marked on the chart.
Example:
Backlash measurement (BL1) = 0.10 mm "a"
Forward gear shim (T1) thickness adjustment
= –0.19 mm "b"
The current shim
decreased by 0.19 mm.
thickness must be
Shimming (regular rotation model)
0.30
0.20
0.10
b 0
–0.10
–0.20
–0.30
0 5
a
A 0 5
B –0.26 –0.22 –0.19 –0.16 –0.12 –0.09 –0.06 –0.02
A. Backlash measurement (BL1)
B. Shim thickness adjustment
4. Calculate the new forward gear shim (T1)
thickness.
TIP:
• Use the lowest number of shims to obtain
the required shim thickness.
• If the calculated shim thickness cannot be
obtained with a combination of the available
shims, increase or decrease the shim thick-
ness by 0.01 mm.
Calculation formula:
New forward gear shim (T1) thickness =
Current forward gear shim thickness + shim
thickness adjustment
Example:
Use the following formula when the shim
thickness adjustment value is positive.
Current forward gear shim thickness =
0.55 mm
Shim thickness adjustment = 0.18 mm
New forward gear shim (T1) thickness =
0.55 mm + 0.18 mm
= 0.73 mm
Use the following formula when the shim
thickness adjustment value is negative.
Current forward gear shim thickness =
0.55 mm
Shim thickness adjustment = –0.19 mm
New forward gear shim (T1) thickness =
0.55 mm + (–0.19 mm) = 0.36 mm
8-42
10 15 20 25 30 35
A (1/100 mm)
10 15 20 25 30 35
0
1
2
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4
5
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10
A