That is a catch can that my friend installed. He didn’t want to direct vent the crankcase for fear of covering the tire with oil. He put on the catch can but also allowed it to breathe to atmosphere on the left side with a filter on the end of the hose. The path of least resistance is to go to the catch can first. I haven’t had to empty the can but there is some oil at the bottom of it. When my friend bought it last year I fell in love with it. He decided to sell it this spring so I had to jump on the opportunity. It has a few bugs to get rid of but is beginning to be a fun ride. It’s a 1976.