71 Demon seat slides back

Oh I see. Maybe some wd40 would loosen it? Are the seats hard to remove? Would rather keep them on, if so. Thanks for the info
It's only 4 nuts to remove the seat. Once you have the seat out and turned over you can see what's going on (or not) and grease it up properly. Spraying WD will probably be a temporary fix if you get it exactly where it's needed. Probably get more on everything but the seat track mechanism plus it drys up quite quickly. I believe it's a little bit of a safety issue so do it right and do it once. Good luck with it.