Special Tool - Outside Circlip Pliers: 57001-144
The 5th gear [A] on the output shaft has three steel balls assembled into it for the positive neutral finder mechanism.
Remove the 5th gear as follows.

Set the output shaft in a vertical position holding the 3rd gear [B].
Spin the 5th gear quickly [C] and pull it off upward.
Transmission Assy Installation
Transmission Shaft AssemblyMeter Unit Circuit (ZX1000J Model)
1. Ignition Switch
2. Joint Connector F
3. Stop Watch Button
4. Oil Pressure Switch
5. Crankshaft Sensor
6. Water Temperature Sensor
7. Gear Position Switch
8. Intake Air Temperature Sensor
9. ESD ECU (ZX1000JD/KD)
10. ECU
11. Rear Wheel Rotation Sensor
12. Engine Ground
13. Battery ...
Front Fork Installation (Each Fork Leg)
Install the fork so that the top plug end [A] as shown in the
figure.
11 mm (0.43 in.) [B]
Steering Stem Head [C]
Tighten:
Torque - Front Fork Clamp Bolts (Lower): 23 N·m (2.3
kgf·m, 17 ft·lb)
NOTE
Tighten the two lower front fork clamp bolts alternately
two times to ensur ...
Water Pump Housing Disassembly
NOTICE
Do not damage the hole wall of the water pump
housing.
Insert a bar [A] into the pump housing [B], and hammer
evenly around the circumference of the mechanical seal
bottom [C].
Take the oil seal [A] out of the housing [B] with a hook [C].
...