its basically like a drain plug. In case you get water in your airbox you can remove it to drain. If you dont ride through lakes or rain you could just plug it permenently, or if you leave it open it will just suck in more air from there, but it probably would be dirtier air than from up top......know what I mean?
yea i know what you mean the reason i am asking is because my 06 yfz450 seized up after i rode into some deep water water and i thought some water could of got in there because my air box doesnt have one on there its just an open whole.
what was the deepest water anyone has ever been in with there yfz's and not had any problems after