If you ride in Southern California under "dusty conditions", you will have to clean your air filter after 2 or 3 rides. Less often if you ride in winter after the rains (the perfect riding time).

Your air filter is located under the seat, and on most bikes is accessible through a side cover.
(usually the right side). The filter is made out of foam and is impregnated with a very sticky "air filter oil". By the time you are servicing it, it will be sticky and very dirty!

a.    Open side cover and retrieve the filter (is convenient to use latex gloves).

b.    Wash the filter with a solvent (or kerosene) to get all the oil out.

c.    Wash the filter in a solution of warm water and a mild soap to get all the dirt out.

d.    Gently rinse the filter with clean water, without twisting it excessively

e.    Let it dry fully (hanging it in a vented are overnight will do).

f.    Now you are ready to impregnate the filter with "air filter oil" and re install it.
      (make sure you  spread the oil evenly all around the filter and gently squeeze the
       excess).

    Note: There is a new product on the market that we highly recommend because
              is environmental friendly (bio-degradable) and also will make your life easier since
              you can do all the cleaning in the kitchen sink.
              The product is called NO-TOIL AIR FILTER OIL, and when you buy it it comes with
              a bottle of a specially formulated "cleaner" that chemically reacts to the product making
              the cleaning process a breeze!