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

Check 3-6: Neutral Indicator Light (LED) Inspection
Meter Unit Circuit (ZX1000J Model)Battery Maintenance
It is the owner’s responsibility to keep
the battery fully charged. Failure to do
so can lead to battery failure and leave
you stranded.
If you are riding your vehicle infrequently,
inspect the battery voltage
weekly using a voltmeter. If it drops
below 12.8 volts, the battery should be
...
Separator Operation Test
WARNINGGasoline is extremely flammable and can be
explosive
under certain conditions. Turn the ignition
switch OFF. Do not smoke. Make sure the area is
well-ventilated and free from any source of flame
or sparks; this includes any appliance with a pilot
light.
...
Operating Procedures
Clean the seat area carefully.
Coat the seat with machinist’s dye.
Fit a 45° cutter into the holder and slide it into the valve
guide.
Press down lightly on the handle and turn it right or left.
Grind the seating surface only until it is smooth.
NOTICE
Do not grind the seat too ...