You can find the following oil filters, which are a direct replacement for the Kawasaki unit sold by dealers. Most are around half the price of the Kawasaki filter:
At least one of these filters will be available at any reasonable auto parts store, such as AutoZone, Pep Boys, Schucks/Kragen, NAPA, WalMart, etc. If you can't find these brands at your favorite auto parts store, check to see if they have a cross-reference chart for the brand of filters they carry -- most filter manufacturers do. Cross-reference their brand to one of those filters listed above.
Another choice is to purchase a "reusable" filter, such as that produced by Scotts, and available on their website, http://www.scottsonline.com. Scotts claims their reusable filter works better than a paper filter, and though it costs ten times as much as a Kawasaki paper filter, it should ideally last as long as the motorcycle and provide at least equivalent filtration to a paper filter.
Created by Ian Johnston. Questions? Please mail me.