Hello:
Is your bike an A-3 or an A-4?
If so, the US and Canadian models have an oil level warning indicator, along with the oil pressure sender. Added in 1981.
Troubleshooting guide for oil Pressure/ Level Warning System is listed on page 319 (supplement section) of the Kaw shop manual. Figure N58 takes you through a thorough troubleshooting tree to find out if your light is related to pressure, or oil level.
You did not mention if your oil level is at normal level. If it is, you may have an oil level indicating problem, not related to oil pressure.
Once in a while, if I am a quart low, my oil light comes on, but it's related to oil level, not oil pressure. Single light for both systems.
TO RULE OUT PRESSURE, THIS BEING THE MOST IMPORTANT:
**: Possible relief valve (Stuck open or closed) If pressure is above 85psi, your relief valve is stuck in the closed position. If the oil pressure is much lower than 63psi, at more than 5,000RPM, your relief valve is stuck open.
**: With a warm engine, your pressure should read 28PSI @ 4,000RPM.
**: Do you have battery voltage going to the oil pressure switch? Does the light turn on with the key on? (as an initial self-test?) Engine not running. You could have a defective oil pressure switch. Ohm out the switch (on the 1ohm range) Engine stopped, ohm meter should read zero ohms. When the engine is more than idle RPM, Ohm meter reads off, or infinity. (Switch open) thereby keeping the light off.
IF YOUR LIGHT IS RELATED TO QUANTITY:
**: Oil level sensor inspection. sensor installed, remove the RH side cover, disconnect the yellow lead beneath the regulator rectifier, which connects the oil level sensor to the oil level warning light.
a:Should read battery voltage from the main harness.
b: ohm out the sensor with the 1ohm scale, with the connector removed from the main elec harness. + lead on the yellow sensor wire, - lead to ground, should read 0.5 Ohms with correct oil level. If oil level is empty, the ohm reading should be infinity. (OPEN)
c: is the oil level warning light relay (Green connector in the tail piece) connected? There are procedures to test that relay in the Kawasaki Shop manual.
Hope this helps, keep us posted.
Todd.
The manual provided other tests but the ones listed above are the highlights.