http://cgi.ebay.com/ebaymotors/13-3-8-RFY-Air-Shock-Absorbers-Banshee-YFZ-Warrior-ATV-_W0QQcmdZViewItemQQhashZitem2a0c970b38QQitemZ180599851832QQptZMotorsQ5fATVQ5fPartsQ5fAccessoriesThats what Im going to run on my 1971 R5. They come pretty highly recommended, especially for that price. Look them up on EBay, as they come in a few different colors as well.
After some consideration I think I am going to go with some period-based cafe style shocks. You can pick up a pair of NOS Hammerhead shocks on ebay for about $200 including shipping. I have to admit, I love that upside-down reservoir look Anybody have any experience with these?hammerhead by jkluesner, on Flickr
Omars has the Hammerheads, I've been looking at buying a set for a while and still think I still may. Let me know what your experiance with them is. Here is a link http://www.omarsdtr.com/shox2.html
Here's a shot of the Koni's already on my R100 café: