So the folks here that get their air filters filthy in 400 miles... what setup are you running at the front end? I have an 18 and it has the stock snorkel facing the rear, and the coarse foam prefilter. I have been neglecting my air filter (at 1300 now). I should have learned my lesson with the 500 (had to check air filter every other tank of fuel).
To those with 18's or newer and the updated front end intake, what are you seeing for mileage when changing filters? I have not ridden in excessive dust yet. Mostly road miles.