My brother drug home a 77F that sat in a boneyard with the plugs out. The clutch was a giant ball of rust. I didn't go any further and sent it home with him. On the other hand I got one that leaned against a clothes pole for years with no carbs. The intakes were stuffed with plastic bags and it had moss on the rocker cover. It was beautiful inside. That's the one that was 750, 836, 900 or 936 depending on how many beers the po had at the time. It was bone stock but I bored it and run it in my K0 now.
I looked at one 750 that sat for years leaning against a leaky tractor tire full of chloride, it was ate the F, up. One of the worst I ever saw. $300 with a title and I passed on it.