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

Check 3-6: Neutral Indicator Light (LED) Inspection
Meter Unit Circuit (ZX1000J Model)Handlebar Removal
Remove:
Steering Damper (see Steering Damper Removal)
Clutch Lever Clamp Bolts [A]
Clutch Lever Assembly [B]
Left Switch Housing [C]
Handlebar Weight [D]
Left Handlebar Grip [E]
Remove:
Front Master Cylinder [A] (see Front Master Cylinder Removal
in the Brakes chapter)
...
Front Wheel Rotation Sensor Removal
NOTICE
The wheel rotation sensor should be handled carefully,
never struck sharply, as with a hammer, or allowed
to fall on a hard surface since the wheel rotation
sensor is precision made. Be careful not to get
water or mud on the wheel rotation sensor.
Do not try to disassemble or repair t ...
Hoses and Pipes
Hose Installation
Install the hoses and pipes, being careful to follow bending
direction. Avoid sharp bending, kinking, flattening or
twisting.
Run the hoses (see Cable, Wire, and Hose Routing section
in the Appendix chapter).
Install the clamp [A] as near as possible to the hose end
...