Signs of a Bad Motorcycle Battery

Before diving for your jumper cables, consider the fact that many electrical and mechanical problems can masquerade as a dead battery. Some are simple, and others can be costly and involved to repair.

Many modern motorcycles use a small push-button switch under the engine to keep a rider from blasting off into the sunrise with an extended kickstand. If your kickstand is up, and the bike won't fire, this switch may be faulty. Consider, too, that if your headlight comes on and is typically bright, and your horn sounds normal, a dead battery is unlikely.

Telltale signs that the problem is the battery include weak or nonfunctioning lights and horn. These hints are usually accompanied by little or no response when the starter button is pushed. You may hear a faint "click" and maybe even the engine attempting to turn over, but if your battery is really toast, silence is the strongest clue.

Some motorcycles require no tools to access their batteries. Some machines seem to expect several hours from a mechanical engineer wielding a bucket full of professional tools to get anywhere near it. Whatever the case may be, consult your bike's owner's manual. It should include detailed instructions explaining how to uncover the battery's positive (red) and negative (black) terminals. If you have no manual at your disposal, you'll have to find the battery yourself. Try looking under the seat.

If you've never dealt with a motorcycle or car battery before, keep in mind that it is never alright to let anything conductive connect the positive (red) terminal of your battery to any other metal part of your bike. Doing so will certainly fry a battery with even a modicum of voltage left in it, and possibly fry you as well. If you have trepidations about testing your battery on your own, consult a professional.

With the battery terminals uncovered, you will need a voltmeter or multimeter to proceed. These cost as little as $10 at an autoparts or home improvement store, and instructions for their specific use are included in this article's reference. Turn the control knob on the multimeter to measure DC Voltage, and select a voltage range that includes 12 volts. Many voltmeters and multimeters have a setting for 20 volts, which will work handily. Touch the black lead of the multimeter to the negative (black) terminal of your motorcycle's battery, and touch the red lead of the multimeter to the positive (red) terminal. If the voltage shown on the multimeter is less than 11 volts, your battery should be charged (13 to 13.6 volts is ideal).

The “Resources” link explains how to jump start a motorcycle with a dead battery. This is a passable temporary fix, but if you start the bike this way, you should monitor the battery's voltage after riding it for a while. If it has not improved, your bike may have problems with its charging system, and/or the battery may be past its prime and need replacement.