Can't find upper engine oil leak!

My 1982 KZ750H3 has a leak somewhere in the top of the engine that I can't seem to locate. It wets the upper cooling fins on the left side and sometimes pools around the base of plug #1. The valve cover gasket and side rubbers are new. I've tried sealing around the gasket outer edge to try to stop it without luck. Any ideas? Thanks!

Degrease the engine,let it dry/blow the water off with compressed air and then using a spray of powered foot de-oderizer or athlete's foot powder, lightly spray the suspicous areas.

The foot powder will wash off with water telling you where the leak(s) are.

Mechanical tach drive? One way to find leaks is to clean the engine as best you can. A high flash point solvent works well for this. Something like Birchwood Casey gun scrubber. When dry, sprinkle talc (baby powder) around the suspect areas and then start the engine. Even a small leak will show up quickly in the powder.

Dang, I need to type faster.

MFolks and TexasKZ, you both had the same idea, so I'm guessing it's a good one. Let me see if I have this right; Clean the engine well and then use a spray foot powder to coat the suspected areas. Run the bike and the leaking oil will wash the powder away where the leaks are. Right? MFolks said: "The foot powder will wash off with water telling you where the leak(s) are." ...but wouldn't water wash it all away erasing the evidence? Slightly confusing. And what is a good spray foot powder for this?

I should have said after finding the leak, to mark where it's coming from(maybe a marker) and then wash off the powder with water.

I've also been looking for another leak at the bottom of the engine (left side) which causes a lot of smoking. When I removed my lower left side cover (sprocket/shifter cover) I discovered a round cap held to the engine with two Phillips screws. feeling around that cap, it was dry till I got to the bottom screw, which was soaked with oil. In the picture below, one arrow points to the screw and the other points to the inside left exhaust pipe which is covered with oil, resulting in the smoking problem I've been having.

Haven't taken the cap off yet, but I suspect that is the source of the leak. Is there a gasket behind it, and what is behind that cap? Does this sound right?

That cap covers the driven shaft from the crank, it also holds the starter clutch. The plug has an O ring and it probably has gone flat on the edges, replace the O ring and no more oil leak - the exact same thing happened to mine. To stop it temporarily, try put some grease around the O ring and refit, this should stop the leak for the moment but you will need to replace the O ring.

Noel