With the top removed, the air filter does nothing as the air isn't being pulled thru it. The throttle bodies are wide open to suck up any and all crap in the air..
Just curious, what are you trying to accomplish?
(There is a mod to drill the air box if you want more intake noise)
BTW, Removing it altogether for separate filters will also allow all that nice hot air from the engine to get sucked in. The stock intake opening is much farther away and closer to cooler air..
Just watching the air temp gauge - 12 min of idle time in traffic and the whole box is heat soaked on a hot day. You need fresh air and that's not gonna happen from under the tank unless the engine is CONSUMING IT!!!
WOT all the time keeps the air Fresh and not Heat soaked! Blah