I emailed ProMoto Billet, asking if they might make a rack specifically for the KX450F (they are thinking about it). They make one for the KLX450, which I bought and made a couple of modifications to make it fit. My first attempt was lamer than my second, and the second is slightly lame, but thought I would post anyway. Danger is posting his application on a KX500AF so it is somewhat different on the exhaust side. First picture here is what the first attempt looked like. It was sticking up a little bit high from the fender.