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

Check 3-6: Neutral Indicator Light (LED) Inspection
Meter Unit Circuit (ZX1000J Model)Maintenance and adjustment
The maintenance and adjustments outlined in this chapter must be carried
out in
accordance with the Periodic Maintenance Chart to keep the motorcycle in good
running condition. The initial maintenance is vitally important and must not be
neglected.
With a basic knowledge of mechanics and the ...
Piston Removal
Remove:
Crankshaft (see Crankshaft Removal)
Remove the piston together with the connecting rod to the
cylinder head side.
NOTICE
Discard the connecting rod bolts and nuts. To prevent
damage to the crankpin surfaces, do not allow
the connecting rod bolts to bump against the
crankpins. ...
Throttle Grip and Cables
Free Play Inspection
Refer to the Throttle Control System Inspection in the Periodic
Maintenance chapter.
Free Play Adjustment
Refer to the Throttle Control System Inspection in the Periodic
Maintenance chapter.
Cable Installation
Install the throttle cables in accordance with the Cable,
...