Check out the web site that Alaska Boy posted in the "oil filters" post. www.motorcycleinfo.calsci.com I was in there today looking to see what kind of info they had on filters both oil and air. There is an article on K&N filters that you will find quite interesting! Let's put it this way...Right after reading the article i went to town to get a paper filter for my truck! and scrap that K&N! I would recommend that anyone who thought about purchasing one or who has purchased one to check this out first....Glad i did. Thanks Alaska Boy! you may have just saved me a few grand!