Gustafsson Plastics makes new windscreens for all of the early 1st Gen Interceptors. 500, 750's, and the 1000's. I found they had the clear screen I needed for my 83 HRC Project Build. Unfortunately they are definitely not cheap as the 83-85 screens were $129. But nobody else really has them and if you really want a new one then where else do you go? They are at www.bikescreens.com Oh and I should mention that you also get the bonus of having to make you own mounting bolt holes in the screen. They recomend buying one of their special drill bits but they never worked for me so I have for a long time used a Dremel tool and one of the Dremel bits to make the holes. I have never cracked a screen doing it that way.
