If the display function does not work, replace the meter unit.

Check 3-6: Neutral Indicator Light (LED) Inspection
Meter Unit Circuit (ZX1000J Model)Air Intake Solenoid Valve Unit Test
Remove the air intake solenoid valve (see Air Intake Solenoid
Valve Removal in the Fuel System (DFI) chapter).
Set the hand tester [A] to the × 1 Ω range and connect it
to the air intake solenoid valve terminals as shown in the
figure.
Special Tool - Hand Tester: 57001-1394
...
Swingarm Installation
Visually inspect the chain guide [A].
Replace the chain guide if it shows any signs of abnormal
wear or damage.
Apply a non-permanent locking agent to the threads of
the chain guide bolt [B].
Apply plenty of grease to the lip of the oil seals [A].
Be sure to install the oil seals ...
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 ...