Sounds like someone took the emissions stuff off your bike. I have not done this myself but from reading the manual, that fitting sucks in and without a hose connected I can image what it's sucking in, I would try capping it and see how it runs, someone else with experience might chime in and give you better advice.
On all models, when the engine is running, intake venture negative pressure (vacuum) slowly draws off the hydrocarbon vapors from the charcoal canister through the
canister-to-intake purge hose. These vapors pass through the intake and are burned as part of normal combustion in the engine.
