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

Check 3-6: Neutral Indicator Light (LED) Inspection
Meter Unit Circuit (ZX1000J Model)Lower Fairing Installation
Installation is the reverse of removal. Note the following.
When installing the pad [A], align the edge of the pad and
the marking of the fairing [B].
When installing the pad [C], align the edge of the pad and
the fairing [D], and fit the edge of the pad to the boss [E].
Insert the hoo ...
Serial number locations
The engine and frame serial numbers are used to register the motorcycle.
They
are the only means of identifying your particular machine from others of the
same
model type. These serial numbers may be needed by your dealer when ordering
parts. In the event of theft, the investigating authoriti ...
Air Suction Valve Installation
Install the air suction valve so that opening [A] of the reed
faces downward.
Apply a non-permanent locking agent to the threads of
the air suction valve cover bolts [A], and tighten them.
Torque - Air Suction Valve Cover Bolts: 9.8 N·m (1.0 kgf·m,
87 in·lb)
...