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

Check 3-6: Neutral Indicator Light (LED) Inspection
Meter Unit Circuit (ZX1000J Model)Cylinder Head Installation
NOTE
The camshaft cap is machined with the cylinder head,
so if a new cylinder head is installed, use the cap that
is supplied with the new head.
Install the dowel pins.
Replace the cylinder head gasket with a new one.
Replace the cylinder head bolt washers with new ones.
Apply molybden ...
Piston Ring End Gap Inspection
Place the piston ring [A] inside the cylinder (upper
crankcase), using the piston to locate the ring squarely
in place. Set it close to the bottom of the cylinder, where
cylinder wear is low.
Measure the gap [B] between the ends of the ring with a
thickness gauge.
Piston Ring End Gap ...
Check 3-4: Turn Signal Indicator Light (LED) Inspection
Connect the leads in the same circuit as Check 3-2.
Connect the terminal [5] to the battery (+) terminal.
Connect the terminal [6] to the battery (+) terminal.
Check that the turn signal indicator light (LED) [A] goes
on.
If the indicator light does not go on, replace the meter ...