Air filter? Haven't cleaned it yet...rode 5 k with stock..then went to hi flo (same as stock..) then k&n when I did the last of my mods (3 months...2k miles or so)
So..that is on my list of todos...I just hate the airbox screws
I would think when you change oil though? So 3-5 k
From k&n:
4. How often do I need to clean my K&N air filter?
If you have not experienced a decrease in mileage or engine performance, chances are your filter is fine and does not yet need cleaning. To be more specific, the filter does not require cleaning if you can still see the wire screen on the entire air filter regardless of how dirty it may appear. When the screen is no longer visible some place on the filter, it is time to clean it. When used in normal paved road, street or highway conditions, our replacement air filters that fit in the factory air box should require cleaning every 50,000 miles and our large conical filters on an intake system should require cleaning every 100,000 miles. When used in dusty or off-road environments, our filters will require cleaning more often. We recommend that you visually inspect your filter once every 25,000 miles to determine if the screen is still visible.