I second (third? fourth?) the notion to get one at the hardware store. Buy a few that look like they'll fit and try them out. If none fit, file or dremel one down until it DOES fit. I pulverized about 1/3 of my woodruff key in Austin, and I just stuck a wad of aluminum foil under it to prop it up enough to make it stick out so I could align the flywheel, and then I rode that home ... which involved getting lost on the highway for 10 miles. If a partially destroyed, aluminum-foiled woodruff key can do that for me, I'm sure that whatever you get from the hardware store will be good enough, at least until you can get a real replacement. It doesn't have to fit perfectly; it just has to fit well enough that you can use it to line the flywheel up.