As far as engine parts, there's lots of parts that are universal to the 550s and in fact, all the 4 cylinder bikes (valve guides for example). Go to kasawaki.com, click on "owner info", "parts diagrams" and then to motorcycle, the year, model, etc. You can go through the list of diagrams until you get the one you want (crankcase, wheels, exhaust, etc) and pull it up. find the part in question, write down the part number (the entire number shown on the parts list, not the short number shown on the diagram) and then pull up a 550 of another year and see if the number is the same. Some things like pistons and camshafts will probably be different between the kz and gps models while things like piston rings, crankshaft and so on will probably be the same.
