First, I used an old 18" wheel kids bike (shown below) for the foundation.
The throttle was set up using a length of brake cable and hand leaver from an old Schwinn bike and about a 9" length of cable from the weed eater motor that attached to the throttle butterfly valve. These cables are connected by a clamp. The cable section that goes up to the handle bar lever is fixed in place to the frame ( as shown) so it won't move when you actuate the throttle handle.
I mounted a 25 cc weed eater motor using a piece of angle iron and a piece of carpet metal. The motor is rigidly mounted to bike frame with no turn buckles for tension. Basically it's the tire pressure that determines the friction force between tire and drive spindle. The drive spindle is just a bike peg I took of my kids bike and it screwed on directly to the weed eater trimmer motors crankshaft. There is a length of grounding wire and a spring attached to the throttle butterfly valve to assist in closing the throttle when lever is released. Hopes this helps with how to build your own motorized bike!
Go here to see pictures of the project. http://youtu.be/WOTm8Lq70FM Leave your comments and questions.
