Straight from the 1984 to 1990 FLT manual. I think the captions are swapped as the facing page has the square tank and has late 1984 through 1989 as the description. At least it shows the oil path and the rest should work out with a little adjustment.

 

Late 84 to (at least) 86

 

Thank you to all! You backed up what I thought, it's a breather. What threw me was that the guy I bought the bike from had some type of threaded open canister on the end of this loose hose. He also changed the carb to an S&S and used that air cleaner, not the original. The line I couldn't figure out was the original air cleaner line. It sat awhile and dumped a lot of oil when I started it up, I'm draining the old oil and starting over. Again I appreciate all your comments and suggestions.

 

Yeah, they all do that.

Most of us put a little air filter on the end of the breather line and put the filter thingie down underneath the bike.

The original carb on that bike was total crap. Sounds like you have a good bike, just get it back together and sorted out.