Like car batteries, motorcycle batteries can need a charge from time to time when they are drained of power. You can jump start a Harley Davidson motorcycle battery with a battery from a car in 5 to 10 minutes with a set of jump leads. This will provide enough power to the Harley to start it and get back on the road.
Turn the engine to the car and the Harley off.
Remove the seat of the Harley with a Phillips screwdriver, and unsnap the battery cover on the left side of the motorcycle.
Connect the red positive ("+") clamps to the positive terminals of the Harley battery and the car battery.
Connect one end of the black negative ("-") cable to the negative terminal on the Harley battery. Connect the other end of the black negative cable to an unpainted metal surface on the car engine. Do not connect it to the negative terminal on the car battery.
Keep the cables in place for several minutes then start the Harley. Try again after a few more minutes if it does not start the first time.
Remove the cables, and snap the battery cover on the Harley back into place. Replace the seat with the Phillips screwdriver.
Run the motorcycle's engine for at least 30 minutes to ensure the battery is fully recharged.