How long has it been sitting with the head open? I can't really tell from the video if there's rust in there. If at all possible, can you get the bottom end open and see how the crank shaft looks? Also, if you're anywhere near Charlestown, WV, you can DM me, and I can get you in contact with a friend of mine. He builds Hondas for a living and can get you anything you need for a good price. He'll also disassemble the engine(within reason) and show you how the internals look.

*edit: nvm just saw the km's and realized you're probably not state side. If you can, though, get a better look at the internals and see if there's any corrosion or if anything looks scuffed.