Ok, I bought my bike with 4300 miles. Not knowing exactly the frequency of maintenance, I changed the oil and check the air filter. The air filter was relatively clean, I tapped against the ground and a bit of dirt came out. Well I just hit 12K miles and went to replace the air filter. To my surprise, it was pretty clogged! I don't think the poor thing could get a full breath! My plan is to check it every 3k or so from now on! Take a look at the pile of crap that came out!

Where the heck you riding out in someone's farm field? My home came with less top soil than that! Granted it's a Westport built home but still.

Mine looked about like that after 11000 miles but i never got a pile of dirt out of it. I think even 8000 is too long for me. 6000 is about right.

I ran a filter about 9000 miles it looked about like that pic Rook.

I clean my filter wit each oil change. I found the ZX14 and my ZX10r air filters need much more frequent attention than any other bike I have owned. I assume it is the RAM air system, its a pretty short and direct run to the filter.

Click here for manufacturers service interval.