I changed the stock air filter yesterday for the second time and what a surprise I got. It looked like a forest was growing in the air box. There was allot of sticks and leaves and dirt in the bottom of the air box and some of it was stuck on the filter. Had about 15,000 miles on the filter. I changed it over to a UNI filter. Looks like I will be looking at this every 5,000 miles when I change the oil.