4. Install the middle drive shaft holder (A,
Figure
42
) onto the middle drive shaft and secure the
holder in a vise.
5. Install the middle drive shaft nut wrench (B,
Fig-
ure 42
) onto the nut.
6. Install a torque wrench at 90° to the middle drive
shaft nut wrench and torque the nut to 110 N•m (81
ft-lb.).
7. Stake the threads of the nut to lock it into place.
8. Install the female damper cam and the male
damper cam.
9. Install the damper spring and the spring seat.
10. Compress the spring with the damper spring
compressor (
Figure 41
) and install the spring re-
tainers.
Inspection
1. Inspect the gear teeth on the middle drive shaft
for galling, pitting or chipped teeth. If there is any
damage, replace the middle drive shaft and the mid-
dle driven shaft as a set.
2. Inspect the splines on the middle drive shaft. If it
is damaged, replace both the middle drive shaft and
the middle driven shaft. Also inspect the splines on
the middle driven gear (A,
Figure 35
) for damage.
3. Inspect the mating surfaces of the male and fe-
male sides of the damper cam. Replace both parts as
necessary.
4. Inspect the internal splines on the male and fe-
male sides of the damper cam.
5. Inspect the damper spring for wear, cracks or
damage. Replace the spring if necessary.
Middle Drive Shaft Shim Selection
1. Calculate shim thickness for the middle drive
shaft assembly using the following formula:
a. Shim thickness = 43.00 – (42.00 + A)
b.
A
equals the number on the top of the left
crankcase half.
c. For example, if the number on the upper
crankcase is 46 (
Figure 43
), then shim thick-
ness = 43.00 – (42.00 + 0.46) or 0.54.
2. Middle drive shaft shims are available in three
sizes (0.10, 0.15 and 0.20 mm), round off shim
thickness to the nearest five hundredths of a milli-
meter as follows:
a. If the hundredths digit in the calculated value
is 0-2, round shim thickness down to the ex-
isting tenths digit. For example, if the calcu-
lated value is 0.52, round shim thickness
down to 0.50 mm.
b. If the hundredths digit in the calculated value
is 3-6, round shim thickness to the nearest
five hundredths of a millimeter. In the above
example, the calculated value is 0.54. Round
this up to 0.55, and install the appropriate
number of shim(s). In this instance, install
two 0.20 mm shims and one 0.15 mm shim.
c. If the hundredths digit is 7-9, round shim
thickness up to the next tenth of a millimeter.
For example, if the shim thickness is 0.58
mm, round shim thickness up to 0.60 mm.
MIDDLE DRIVEN SHAFT ASSEMBLY
The Yamaha universal joint holder (part No.
YM-04062 or 90890-04062), or its equivalent, is
needed to remove and service the middle driven
shaft assembly.
Removal/Installation
Refer to
Figure 44
.
NOTE
The collapsible collar must be re
placed whenever the middle driven
shaft assembly is removed from the
housing. Have at least one replace
ment collapsible collar on hand be
fore
beginning
this
procedure.
Consider having two or three collaps
ible collars before starting. If the mid
dle driven shaft nut is overtightened
during assembly, the collapsible col
lar will have to be replaced.
198
CHAPTER SEVEN
43
