Middle Drive Shaft Removal - Yamaha XZ550RJ 1982 Service Manual

1. Calculate the shim thickness using the for-
mula shown below.
Shim thickness (A) = a - b - c
a = 59 plus the number printed on the
crankcase.
b = 42 plus or minus the number found
on the middle drive gear,
c = 16.94 (bearing width)
For example: If the crankcase is marked
"55",
a = 59 + 0.55
a = 59.55
If the middle drive gear is stampled "+02",
b = 42 + 0.02
b = 42.02
A = a-b-c
A = 59.55 - 16.94 - 42.02
A = 0.59
The shim thickness is 0.59 mm (0.023 in)
2. Shims are supplied in the following thick-
nesses:
0.15mm (0.00059 in), 0.30mm (0.0118 in),
0.40mm (0.0157 in) and 0.50mm (0.0197 in)
3. Because shims can only be selected in 0.05
mm (0.0020 in) increments, use the follow-
ing chart to round off the hun-dredths digit
of the calculated thickness and select the
appropriate shim.
Hundredths digit
0,1,2
3,4,5,6
7,8,9
In the example from above, the calculated
shim thickness is 0.59 mm (0.0232 in). The
chart instructs you, however, to round off
the 9 to 10. Thus you should use two 0.30
mm (0.0118 in) shims. 4.
4. Install a new drive axle bearing and middle-
pinion-drive gear onto the drive axle. Install
the lock washer and securing nut and
torque it to specification. Bend a lock tab
against a nut flat.
Tightening torque:
110 Nm (11.0m-kg, ft - lb)
NOTE:
Check the middle drive gear first for signs of pitting,
galling, or other extreme wear. Replace the middle
drive gear and middle drive shaft as a set.
5. Install the drive axle subassembly with the
proper shims into the crankcase.

Middle drive shaft removal

Refer to page 3-12 for removing the middle drive
shaft from the engine.
Rounded value
0
5
10
96