Motorcycles run off the same general system that cars use, which involves a key-started ignition that ignites the engine into action. The key being inserted and turned in the ignition closes an open circuit, which causes the combustion required for the engine to turn on. This action is contained within the ignition wiring, and the ignition is so designed that only your key can fit into the opening. In the event that you lose your keys or you buy an old motorcycle that doesn't come with keys, you can replicate this action yourself.
Locate the ignition wiring coming out of the handlebar area. There will three coloured wires bundled together in a wiring sleeve.
Look along the wiring sleeve until you find the point where the three coloured wires end with a plastic wiring cap along the body of the bike. The cap will have another group of wires plugged into.
Pull the caps apart and let the ignition wiring hang down. Hold onto the lower portion of wiring.
Insert one end of the speaker wire into one of the eyes of cap socket. Bend the wire and insert the other end into another eye. If you don't see the light of the bike turn on along with the click of the engine, try inserting the wires in a different combination until you get results.
Press the ignition button on the throttle to start the motorcycle engine.
Get a spare key cut whenever you get a new key in order to have spare if needed.
Never handle or start a vehicle that you do not own or have permission to gain access to.