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

Check 3-6: Neutral Indicator Light (LED) Inspection
Meter Unit Circuit (ZX1000J Model)Upper Fairing Assembly Removal
Remove:
Lower Fairings (see Lower Fairing Removal)
Center Inner Fairing (see Center Inner Fairing Removal)
Upper Inner Fairings (see Upper Inner Fairing Removal)
Windshield (see Windshield Removal)
Disconnect the front turn signal light lead connector [A]
(both sides).
Remove the bo ...
Rear Fender Front Removal
Remove:
Flap and Rear Fender Rear (see Flap and Rear Fender
Rear Removal)
Fuel Tank (see Fuel Tank Removal in the Fuel System
(DFI) chapter)
Battery (see Battery Removal in the Electrical System
chapter)
Exhaust Butterfly Valve Actuator (see Exhaust Butterfly
Valve Actuator Remova ...
Stem, Stem Bearing Installation
Replace the bearing outer races with new ones.
Drive them into the head pipe at the same time.
Special Tools - Head Pipe Outer Race Press Shaft [A]:
57001-1075
Head Pipe Outer Race Driver,
55 [B]: 57001
-1446 or Bearing Driver Set: 57001-1129
Apply grease to the outer races.
...