So I went to get a new oil filter and air filter for my XT600 to give it a service before getting it registered. Oil filter, $16. Ok, it is smaller than a car, and not in a can for external mounting but still costs about as much. So I ask about the air filter. OEM, $110! (same one made for all models 1990 to 1999) One after market one was $100 and another $130! Why is it then that I can go and buy an air filter for the car, 4 times the size, for about $20, or one fifth the price!!!? And if you base it on dollars per area of air filter, the bike one costs 20 times more than that of a car!!!! I could just about go and buy a car filter, cut it in quarters and silicon a piece into the frame of the bike filter, and save $380 - $500, and I'm seriously considering giving it a go, unless anyone can dissuade me with sound reasoning. I even tried washing out the old one with kero as it was about a quarter contaminated with oil (come back through the carbs?), but I'm not sure I'm happy with the result. Ok, so it isn't a Duc or a BMW, but for a major Japanese manufacturer, I thought the price of this sort of stuff would be a lot less than what it is. Even the Kawasaki EL250 air filter (same motor as GPX and ZZR) was $65, and it is just some foam and plastic. How can they justify the price, even if they don't make as many as car parts?