Replace it if necessary.

Inner Tube Inspection
Spring Tension InspectionSubthrottle Sensor Output Voltage Inspection
Measure the output voltage at the subthrottle sensor in
the same way as input voltage inspection, note the following.
Disconnect the subthrottle sensor connector and connect
the setting adapter [A] between these connectors.
Special Tool - Throttle Sensor Setting Adapter: 57001
-1538
...
Replacement Parts
Replacement parts must be KAWASAKI genuine or
recommended by KAWASAKI. Gaskets, O-rings, oil seals,
grease seals, circlips, cotter pins or self-locking nuts must
be replaced with new ones whenever disassembled.
Assembly Order
In most cases assembly order is the reverse of disassembly,
howe ...
Oil Pressure Switch Installation
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 clean cloth.
Apply silicone sealant to the threads of the oil pressure
switch, and tighten it.
Sealant - Liquid Gasket, TB1211: 56019-120
Torque - Oil Pressure ...