its for draining away oil ,recirculated from the engine breather into the airbox for the fumes, sometimes they leak a lot if the engine is overfilled with oil as the engine pumps it out at pressure
When I got knocked off my bike I fell on the LH side of the bike. Once the bike was upright and started again it spat crud out when the engine was revved. Basically neeed opening, airfilter taking out, and all the oil/petrol mix that had got in cleaining out. Open it up, give it a clean inside and check your oil level is not too high. Also check the air filter is not contaminated.