I wonder if any crank seal from any "80cc ish" engine wouldn't do. I know it is said they are made all over china but i wonder if the seals will interchange.
If you have your old one and an auto parts store that will work for their sale, you might be able to match it up with something there. If not you might try a lawnmower shop but the one here is only a computer match type place. If you don't want it to replace what they have in their computer forget it.
mine blew out the side, all i did was take the gears off, took a srewdriver and went around pring it out. the new one i found a socket that was close in size put the seal in then seated it with the socket and a hammer.