Hi,Tim! You can fashion an air filter into your air box,but it has to be really thin material `cause most peds get restricted too much with regular foam.You have to use a foam that will resist gas without deteriorating.The material on room air conditioners is perfect,but i'm not sure how resistant it is to gas.I would only worry about a pre filter if I had some dirt or gravel roads or constuction zones to travel,though.If you do this you need a backing grid to clip the material into(1/4" X 1/4" wire mesh is perfect).There are filters you might adapt,but the main thing is not to turn them where water and debris are thrown toward the intake holes,and watch out for causing too much restriction,cause it robs your power and mileage and clogs your plug and muffler.I saw where one guy put a `K&N'racing filter on his ped,but I have no idea how to do it other than to `MacGiver' it.BYE!