What is this/what is it for? '78 KZ650 question

While doing some work on my '78 KZ650 today, I noticed this build up on only a particular part of the bike. I followed it back to the pictures below which looks like some sort of valve that is supposed to be threaded shut. Am I just missing the cap, or is it supposed to be open? It is located in the front of the engine directly above the 2 exhaust opening from the right side of the bike.

Welcome KinkJayRoe, that is where the tachometer cable connects.

Thinking that's the tachometer drive that everyone says always leaks. I have a spectre, so I don't have one, but I'm pretty sure someone else will be along shortly to confirm that's what it is.

Yep, the tach drive connection. If it's open like this, you'll be having oil come out when the engine is running, possibly getting onto the exhaust, making a smell of hot oil & smoking.

awesome, makes sense now. Thanks a lot!

I"m thinking it should"nt leak, even if the tach cable is"nt connected, ...you might want to replace the "O" rings in the tach housing before you put a new tach cable, so you dont have oil leaking down your engine, and onto your exaust ...Pete

As stated the tach cable hooks up there. This shows the 2 ends of the cable: