If they show any damage, replace it.

Caliper Fluid Seal Damage
Caliper Piston and Cylinder DamageExternal Shift Mechanism Installation
Install the gear positioning lever [A] as shown in the figure.
Install:
Spring [B]
Washer [C]
Tighten:
Torque - Gear Positioning Lever Bolt [D]: 12 N·m (1.2 kgf·m,
106 in·lb)
Assemble:
Ratchet [A]
Pawls [B]
Pins [C]
Springs [D]
Install the shift ratchet ...
Headlight Bulb Replacement
Turn the cover [A] counterclockwise, and remove it.
Disconnect the headlight connector [A].
Open the clamp [B], and remove the bulb.
NOTICE
When handling the quartz-halogen bulb, never
touch the glass portion with bare hands. Always
use a clean cloth. Oil contamination from hand ...
ECU Identification
Most countries have their own regulations, so each ECU
has different characteristic. So, do not confuse ECU with
each other and use only the ECU for your model. Otherwise,
the motorcycle can not clear the regulation.
ECU Identification
ZX1000JB/KB
ZX1000JC /KC
...