boy's bicycle, which you can usually pick up for a few dollars at a bike shop or junk yard. The basic frame comes from a discarded 26-in. The best part is the machine's lightweight, low-cost design. And when you come to a hill, the torque convertor will automatically downshift to a lower drive ratio to give you rugged hill-climbing power. On flat ground this scrappy little mini bike can hit around 30 mph. Take a small kart engine, add a slick variable-ratio belt transmission and you'll have a real performance 'bear' for half the cost of a commercial motor scooter. We've also found a lot of good information on free mini bike plans at the DIY Go Karts website.
There are two plans - the first uses a junked bicycle for parts, and the second is the super old-school traditional mini bike style. This mini bike is souped up with a torque convertor.
