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 Turn Signal Light Bulb Replacement
Remove the upper seat cover (see Seat Cover Removal
in the Frame chapter).
Disconnect the tail/brake light connector [A].
Turn the socket [A] counterclockwise and remove the
socket together with the bulb.
Push and turn the turn signal light bulb [A] counterclockwise
an ...
Drive Chain Lubrication Condition Inspection
If a special lubricant is not available, a heavy oil such as
SAE 90 is preferred to a lighter oil because it will stay on
the chain longer and provide better lubrication.
If the chain appears especially dirty, clean it before lubrication.
NOTICE
The O-rings between the side plates seal ...
Valve Guide Installation
Apply engine oil to the valve guide outer surface before
installation.
Heat the area around the valve guide hole to about 120
150°C (248 302°F).
NOTICE
Do not heat the cylinder head with a torch. This will
warp the cylinder head. Soak the cylinder head and
heat the oil.
Usin ...