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

Check 3-6: Neutral Indicator Light (LED) Inspection
Meter Unit Circuit (ZX1000J Model)Armature Inspection
Using the × 1 Ω hand tester range, measure the resistance
between any two commutator segments [A].
Special Tool - Hand Tester: 57001-1394
If there is a high resistance or no reading (∞) between any
two segments, a winding is open and the starter motor
must be replaced.
...
Hub Bearing Installation
Before installing the hub bearings, blow any dirt or foreign
particles out of the hub with compressed air to prevent
contamination of the bearings.
Replace the bearings with new ones.
Install the bearings by using the bearing driver set which
does not contact the bearing inner race.
...
Stator Coil Installation
Apply a non-permanent locking agent to the threads of
the stator coil bolts and tighten them.
Torque - Stator Coil Bolts: 12 N·m (1.2 kgf·m, 106 in·lb)
Using a high flash-point solvent, clean off any oil or dirt
that may be on the silicone sealant coating area. Dry
them with a clea ...