We’ve covered weed whacker bicycles before and you can even buy 66cc conversion kits now. [geoff390] posted a few videos over on YouTube about another motor option. In the first video embedded below, he goes over the basic parts of his bike. The chainsaw motor is mounted to the side of the back tire and a metal drive wheel extending from the chainsaw shaft makes contact with it. The motor assembly is mounted on a hinge and the friction between the drive wheel and the back tire is adjusted with a turnbuckle. He posted a more detailed second video in which he goes over some of the finer details of the bike and some of the issues he’s had.