my oil light keeps coming on on my '80 kz750 twin

When I put my engine together in 13, I went through the oil pump. There were wear marks in the plate covering the gears. I had three pumps to work with. I used the best body, plate, gears and measured them with a feeler gauge as per the manual. The plate I used #600 wet/dry paper on a sheet of glass until smooth. I've blown two low pressure gauges and had to go to a 60 PSI Sporster gauge. Cold it's at 10/20 PSI and past 35 on rev. It drops when hot. I'm running 15/40 Rotilla.
I suggest you check out the plate and sand it like I did. They have thinner gaskets for the Z1/KZ's but they are hard to come by now.
The cam chain can cause metal flakes if a guide is worn out and it is riding on the aluminum.
All this suggests a complete tear down is called for.
Steve

I would have to agree with whats been said so far. If the oil light keeps coming on, engine keep getting excessively hot, and there is metallic flakes in the oil??? STOP RUNNING THE ENGINE!!! ASAP!!! The engine still runs...pull it out; break it down and freshen up the bottom end before you do damage that can't be fixed. If you are lucky you may be able to get away with a fresh set of main and rod bearings, a fresh cross hatch hone and some new rings, as well as a set of gaskets. Look into the oil pump as swest suggests to be sure you are getting good oil pressure. No need to wast time rebuilding if there is not enough oil pressure. These engines are not that hard to work on and not very expensive to rebuild.
Good luck, and keep us posted,
Ty

martin_csr wrote: Bountyhunter, is it possible the oil pressure switch is defective or glitchy?
it seems unlikely in this case, but you never know sometimes. ???

Exactly why the first step is always to hook up a proper pressure gauge and see what the pressure is. Possible but the symptoms of low pressure and metal shavings in oil do not sound good.