I am happy to see that you are going to build a KX500 AF from a 250AF frame. I am so impressed with your Honda parts you have to date, and really was trying to figure out how to use your Honda Y section on the Kawasaki frame. Please keep me posted on your progess as you said you would because I think your builds look the cleanest and the most simple. I am from North Dakota and was thinking this would be a great way to cure Winter time blues and build a AF 500 out of my existing KX500 I have now. I havent bought a doner bike yet but was considering the 250F because they are cheaper to buy, and more abundant around here. I am planning on buying a frame on Ebay first, build it around the 500 motor, then buy a complete bike later to finish the project.