Hello from a little town on Oregon named Boring (No kidding) I thought I might as well get my feet wet and introduce myself. HI ! I have built two bikes over the years the first one (In 1993) used a Ryobi Motor(off of a scrap weed eater) with a friction drive to the rear wheel on a 26" mountain bike. I used a urethane skate board wheel that I turned down to about 1" on my lathe for the motor drive. It worked but was to hard on the tires and slipped when wet. I also never go around to installing a kill switch on that thing and I several exciting moments. Actually it was far more trouble than fun and I sold it on to some one who wanted the motor for an RC plane. Several weeks ago I was in Beijing for the Olympics (Work) and I saw so many neat home built motorized bicycles that I got the bug again. So I built another one, This time using a 68CC Happy time motor, I did not like the idea of driving the rear wheel off the spokes so I machined a hub adapter and recut the center hole of the sprocket on my lathe. I put a limit of 200 dollar limit on the whole project and I am currently at 190 dollars spent, I got the Bike for free just need two new tires (7.99 each at Bimart end of season sale) and some adjustments, the motor kit was $160.00 and I got the Bike computer ( Digital speedo ) for 8 bucks at the same sale) the rest was for the the metal and other supplies used for the hub adapter. Kind of a long winded intro. Hope I did not Bore you !!!