Reasons Why a Motorcycle Won't Start, the Horn Doesn't Work, and the Headlight Doesn't Light Up?
2 Answers
It is likely a battery issue. Check whether the two main battery cables are loose or oxidized, and then check if the battery is severely depleted. The battery uses lead plates filled with sponge-like lead as the negative electrode, lead plates filled with lead dioxide as the positive electrode, and 22–28% dilute sulfuric acid as the electrolyte. During charging, electrical energy is converted into chemical energy, and during discharging, chemical energy is converted back into electrical energy. When the battery discharges, metallic lead acts as the negative electrode, undergoing oxidation and converting into lead sulfate; lead dioxide acts as the positive electrode, undergoing reduction and converting into lead sulfate. When the battery is charged with direct current, lead and lead dioxide are generated at the two electrodes, respectively. After disconnecting the power source, it returns to its pre-discharge state, forming a chemical battery. A lead-acid battery is a rechargeable battery, also known as a secondary battery. Its voltage is 2V, and typically three lead-acid batteries are connected in series to achieve 6V. Automobiles use six lead-acid batteries connected in series to form a 12V battery pack. Ordinary lead-acid batteries require periodic replenishment of distilled water to maintain the electrolyte as 22–28% dilute sulfuric acid after some use.
I've seen this situation many times, and it's usually due to a power supply failure. The battery running out of power is the first culprit: either the battery is aging or severely depleted. If the voltage measured with a multimeter is below 12V, it definitely won't work. A blown main fuse is another critical point—it controls the entire circuit. Once it blows, all electrical devices stop working. I usually open the box under the seat to locate and replace it. Loose battery terminals or corrosion (green patina) should also be cleaned promptly; a bit of sandpaper can do the trick. If the charging system fails, such as issues with the generator or regulator, the lights will gradually dim while riding, and you'll need to visit a professional shop for diagnosis. Safety first! Riding without lights at night is risky, so don't push it—pull over and figure things out first. Regular maintenance should include checking connections to prevent problems before they occur.
