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

Check 3-6: Neutral Indicator Light (LED) Inspection
Meter Unit Circuit (ZX1000J Model)Evaporative Emission Control System (California
model only)
This system routes fuel vapors from
the fuel system into the running engine
or stores the vapors in a canister when
the engine is stopped. Although no adjustments
are required, a thorough visual
inspection must be made at the intervals
specified by the Periodic Maintenance
Chart.
Inspection
...
Loading and accessories information
WARNINGIncorrect loading, improper installation
or use of accessories,
or modification of your motorcyclemay
result in an unsafe riding
condition. Before you ride the
motorcycle, make sure it is not
overloaded and that you have
followed these instructions.
With the ...
Battery Installation
Visually inspect the surface of the battery container.
If any signs of cracking or electrolyte leakage from the
sides of the battery.
Put the battery into the rear fender
Install the band [A].
Connect the positive (+) cable [B] (red cap) to the positive
(+) terminal first, and then ...