Building a legal scooter can be a fun project, but it takes time, energy and bit of cash to make happen. The best way to go about the project is to look around for a non-working scooter you're interested in and buy it at a low price. Then, bit by bit, restore the scooter until it is working again and ready to be registered. Not only will you enjoy working on the project, you'll also enjoy riding a vehicle you've built just about from scratch.
Use the Internet and your local newspaper to scan the classifieds for ads selling the scooter you're interested in restoring. Purchase a used, non-working scooter by looking for barn finds or old broken-down scooters someone wants to get rid of. Bring it home in the back of a truck or trailer, and place it in a workspace with proper light. Use a screwdriver, crescent wrenches and a socket wrench and sockets to dismantle the scooter into parts.
Spray paint the body parts your desired color after covering them with primer or have them painted by a professional painter. Wash the engine with a solvent and disassemble it with a socket wrench and crescent wrenches while letting the body parts dry. Download a factory manual for your particular scooter from the Internet so you can follow the diagrams on how to rebuild the vehicle.
Start with the engine, rebuilding it from the transmission outward. Install new engine gaskets obtained from the Internet or your local scooter part supplier. Attach the rear wheel up and tighten it on with a socket wrench. Purchase a new wiring harness and install it through the scooter body so all the wiring is in place. Use a coat hanger if you need to fish it through the body.
Install the front fork of the scooter though the body after attaching the front fender, suspension, and front wheel with a new tire and tube to the fork using a socket wrench and crescent wrenches. Attach the headset to the top of the front fork once it is in the scooter body. Route the wiring upward and into the various electrical connections in the headset. Attach all the wires and the handle bars.
Install the engine into the scooter body and connect it by inserting the front main, swingarm bolt through the body and the engine. Tighten it with a socket wrench. Connect the rear of the engine with the rear suspension to the back of the scooter body. Bolt on the rear wheel with a new tire and tube and tighten everything down with a socket wrench. Attach the carburetor to the engine intake with a crescent wrench.