Wow. Thats looks like a lot of fun. I used to be pretty big into vintage sleds, but I got out of it because parts are just too darned hard to find. Ive owned a '78 Polaris TX 340, a '78 Ski-Doo 340 RV and an '80 John Deere TrailFire 340.
Ive been keeping an eye out for a vintage Yammie, but as of yet I havent found any that didnt need major work. In a lot of ways, I actually think the vintage stuff is more fun to ride than the new stuff because they are so much simpler, lighter and easier to throw around.