Headlight problem, reserve lighting unit?

So heres the skinny:
I just bought a 1982 Kawasaki KZ750-E on which the headlight doesn't work properly. The guy I bought it from said that it started getting dim, then just didn't work one day. He had been using it by running the spare connectors in the headlight housing directly to the high beam, and removing the fuse when he didn't want to use it. Obviously this won't pass inspection. Ive been running through the system with my multimeter checking for continuity and have run into a problem. The low beam line doesn't have continuity to the battery, but the high beam does. I'm confused because it seems as though atleast the high beam should work, but since it doesn't I'm leaning to believe the reserve lighting unit is faulty. Any insight? Is this even possible?

Pardon my dumb question - my bike is older than your KZ750 so it doesn't have some of the later gadgets. What is a "reserve lighting unit?" Ed

Its basically a relay that all the lighting connects to so if there is a failure, a warning light will turn on.

Actually a fail safe, turns on the other beam when one burns out, low goes, high turns on.
Here is a wiring diagram in "File Base" here on kZR. www.kzrider.com/filebase/doc_download/311-z750e3
Don't forget the ground, which is black/ yellow. Power and ground to the head light.
Using the diagram you'll see where to test. Could be a bad switch, bad ground, or connection in the head light bucket.

I ran through the diagram yesterday, the ground has continuity to the chassis, and the high beam line has continuity back to the positive feed when the switch is in the proper posistion. I tested the switch, it works as its supposed to, the reason I'm thinking its the RLU is because its the only thing between the switch and the fuse box.

It can be UN-plugged and by-passed for testing purposes. Remember, a continuity check will not show a bad connection like a test with a current pulling device, like a test light. I would use the head light its self, with some jumper wires. As it will pull over 4 amps when lit. A continuity check will only put a small voltage, and almost no amperage through the circuit.
Load it to be sure of the connection, and voltage drop when under load is also very important.

Remove the RLU, then jumper the blue wire to the blue/yellow wire on the RLU harness connector. That will bypass the RLU.

Interesting! Thanks for the info. Ed

Thank you Motor Head and loudhvx! I jumped the wires as suggested and the headlight works perfectly. I ordered a new one and am anxiously waiting!