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

Check 3-6: Neutral Indicator Light (LED) Inspection
Meter Unit Circuit (ZX1000J Model)Rear Fender Front Installation
Installation is the reverse of removal. Note the following.
Run the harness, cables and leads correctly (see Cable,
Wire, and Hose Routing section in the Appendix chapter).
When installing the clamp [A] on the rear fender front [B],
install it so that the clamp positions at near the ...
Throttle Body Assy Assembly
Before assembling, blow away dirt or dust from the throttle
body and delivery pipe assy by applying compressed air.
Replace the O-rings [A] of the joint pipe [B] with new ones.
Apply engine oil to the new O-rings, and insert it to the
delivery pipes [C].
Insert the joint pipe so th ...
ECU Removal
NOTICE
Never drop the ECU especially on a hard surface.
Such a shock to the ECU can damage it.
Remove the upper air cleaner housing (see Air Cleaner
Element Replacement in the Periodic Maintenance chapter).
Lift up the ECU [A] with rubber protector [B] to disconnect
the connectors [C]. ...