First, be aware that jump-starting any vehicle with electrical cables is hazardous, whether it’s a car, truck, boat, motorcycle, tractor, airplane or anything else! It’s because making the final connection invariably causes a spark, and there are explosive- not just flammable- materials nearby! Lead-acid batteries found in the majority of internal-combustion vehicles are producing hydrogen gas during their normal work cycle. People have been burned, blinded and worse when they created a spark near hydrogen gas and/or fuel!
That said, there is a safe way to do it. You’ll need a jumper cable and preferably a helper.
- Turn off the ignitions of both vehicles.
Connect one of the red jumper cable clamps to the positive terminal (red) of the motorcycle battery and ensure the black clamps at both ends of the jumper cable are not touching anything.
- Connect the other red clamp to the positive post of the car battery. Remember “positive to positive.”
- Connect the black clamp near the car to the negative post of the car battery. Many new cars are provided with negative posts several inches away from the battery for this purpose— use it if it is available. Keep in mind that the jumper cable is energized once this connection is made and extreme caution is now required.
Carefully connect the black clamp near the motorcycle to an unpainted area on the frame of the motorcycle, away from the fuel tank, fuel lines and the battery. You may see a spark when the connection is made because of the voltage differential between the car and the bike. This is normal and this is why you are following these instructions to avoid a fire and possible explosion.
- Do not turn on the ignition of the car. Doing so could potentially damage the car’s electronic system. Some people believe that the car should be started, but if its battery is good and if the jumper cable is properly connected the relatively huge car battery will have no trouble jump starting the bike. Why risk damaging the car or the bike, for that matter?
- Start the bike as you normally would, but crank it no more than 15 seconds. Bike starters are built light and are not designed for long periods of cranking. If the bike doesn’t start after 15 seconds of cranking there is probably something else wrong. Stop cranking and check other systems while the starter cools. Is the stop/run switch on? Check the fuel level and the choke if there is one. Give the starter a minute or more to cool down before trying again.
When the bike is running smoothly, disconnect the black clamp at the bike and then disconnect the black clamp at the car. Disconnect the red clamps at both vehicles. The cables are no longer energized and you and your helper can pat each other on the back for a job well done! The bike probably needs to run at highway speeds for 30 minutes or so before it can be started with its own battery, but even then it won’t be fully charged. Put it on a small charger after the ride. Better yet, charge the battery instead of jump-starting the bike. Good luck!