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

Check 3-6: Neutral Indicator Light (LED) Inspection
Meter Unit Circuit (ZX1000J Model)Exhaust Butterfly Valve Cable Removal
Remove the fuel tank (see Fuel Tank Removal in the Fuel
System (DFI) chapter).
Open the clamp [A] and free the cables.
Slide the dust covers [B].
Loosen the locknuts [A], and turn the adjusters [B] to give
the cable plenty of play.
Remove the clamp [A].
Remove the up ...
Oxygen Sensor Removal (Equipped Models)
Remove:
Fuel Tank (see Fuel Tank Removal in the Fuel System
(DFI) chapter)
Right Lower Fairing (see Lower Fairing Removal in the
Frame chapter)
Disconnect the oxygen sensor lead connector [A].
NOTICE
Do not pull strongly, twist, or bend the oxygen sensor
lead. This may cause the wi ...
Cooling System Flushing
Over a period of time, the cooling system accumulates
rust, scale, and lime in the water jacket and radiator. When
this accumulation is suspected or observed, flush the cooling
system. If this accumulation is not removed, it will clog
up the water passage and considerable reduce the efficiency
...