Preparation

• 1). Search for and buy an old bike that has its powertrain in working condition. With its common availability, cheaper rate and simpler construction with both transmission and engine in the same unit, Harley-Davidson Sportsters are among the best choices.
  
  
• 2). Strip down the frame by removing the engine and transmission. Also, check if you want to increase the power of your bike from its current capacity. In general, it is easy to increase the power of the engines by getter larger cylinders and pistons, and you may want to increase an 883 cubic centimeters (cc) engine to a 1200 cc or so.
  
  
• 3). Check different dealers who sell frames and then buy a frame kit that suits the engine that you have. You could opt for buying just the frame and a second-hand fork in place of a complete chassis to save some money.
  
  

Chassis

• 1). Buy six steel pipes that are 5 feet long and 3 inches thick. Create the frame for the bottom rails, steering yoke and central brace by cutting five of these metal pipes to 4.5 feet. The bottom rails and central brace will support the frame, and the steering yoke will be the horizontal tube that supports the handlebars of the motorcycle.
  
  
• 2). Put three of the 4.5-foot-long pipes and attach two aluminum plates for mounting the engine. Check for the space and design requirements so that the bike has comfortable space for sitting, then weld the mounting plates and the center of the bottom rails to create the structure of the chassis.
  
  
• 3). Weld the bottom rails by applying some solder to the yoke section after placing the steering rod in the middle of the steering piece. Once done, weld the rotating steering tube and the brace plate so that the frame of the motorcycle looks proper. Generally, the frame pipe of a motorcycle is narrower than its steering tubes.
  
  

Construction

• 1). Strip down the parts of the bike including the wheels and brakes and reaffix them to the new chassis that you created. Install the fork, if you did not buy a rolling chassis.
  
  
• 2). Attach the major parts like engine, transmission, gas tank and controls to the bike, and then follow it up with attaching the other accessories like lights and seat.
  
  
• 3). Ensure the bike is working properly, then get it painted at a paint shop.