It is possible. You will have to modify the 250's frame to accept the 500 and I think you have to modify the exhaust to get it to fit. Look around on the web, I have heard of many of these concoctions.
also service honda sells a low boy pipe that's made for the kxf450/kx 500 conversion. you will probably have to "tweak" it a little to fit it in. but that seems to be the closest pipe available to the general public.
Yup, pretty easy conversion, the thread links to pictures of 1 of my 500's, most difficult is pipe and swingarm, pipe issue is solved with the purchase of a service kawasaki pipe, it's not a direct replacement like it's supposed to be but pretty easy to get to fit. that leaves the swingarm and I'm pretty sure it wouldn't be much of a mod job. Do it and you'll have one sweet ride.
A forum community dedicated to Kawasaki Motorcycle owners and enthusiasts. Come join the discussion about performance, modifications, troubleshooting, maintenance, off-road, touring, street bikes, and more!