There was an aftermarket filter on the end once. Looks like it broke off. No big deal. It's kinda optional.

 

This^^^

 

That pipe once vented to the stock airbox IIRC. Leaving it short can indeed make an oily mess, as the crankcase is breathing through it. With my bike I mounted a small air filter under the seat, fastened to the frame cross-member.

 

as mentioned by others … the vent most likely had a filter on it at one time, not a big deal that it is missing … with the bike sitting for some time the oil that was in the tank slowly made its way into the crankcase … making it look like there is no oil … you added 3 quarts in the tank not knowing there was the same amount sitting in the crankcase waiting to go back into the tank … once you started the bike the pump tried to put the oil in the crankcase back into the tank, but there was no room so it got pushed out the vent …

you can drain the system and start over … you may want to run the engine a little before draining to make sure most all of the oil is back in the tank

 

The "chrome cap" probably looked like that at some point in time.




It's probably going to push a LOT of oil out that hose when you start it and a lot will return to the tank so be prepared for big mess.

I would remove that hose and attach the 90 bend to the outlet on the engine case (routing it downward) and put a drain pan under it. Make sure to remove at least 1/3 - 1/2 of the oil from the tank as the oil pump will return it to the tank fast as it can. Let it idle or fast idle (don't rev it) for 2-3 minutes and recheck the tank. Restart and run a few more minutes and repeat previous sentence. When it stops dribbling oil out the breather hose re-check the oil tank and go ride for at least 20 miles. That will get everything (oil) back where it belongs. All this is very common with bottom breather engines that have sat a long time.