On most of these bikes, you'll see 2-3 hoses that dead end in front of the rear tire area (great place to dump anything). One is a battery vent, one is a fuel tank overflow and the third could be from a purge system for the various state emissions or even a crank breather that was rerouted. There are other non terminated hoses also such as the trans vent line. Follow the hoses back to the termination point and you'll see where they go to for a better understanding.
What's connected to the other end of that hose showing right at the corner of the cylinder inside the primary?
What's connected to the other end of that hose showing right at the corner of the cylinder inside the primary?