If your motorcycle shuts off when you turn on the lights, it could indicate an electrical issue. Here are a few possible causes for this problem:
Battery issues: Insufficient power from the battery can cause the motorcycle to shut off when additional electrical loads, such as lights, are turned on. The lights draw power from the battery, and if the battery is weak or not adequately charged, it may not be able to handle the additional load, resulting in a loss of power. Check the battery's condition, terminals, and charging system to ensure they are functioning properly.
Faulty charging system: A malfunctioning charging system can lead to a weak or discharged battery, causing the motorcycle to shut off when electrical loads are activated. The charging system consists of the stator, regulator/rectifier, and battery. If any of these components are faulty, the battery may not receive sufficient charging while the motorcycle is running. Have the charging system inspected by a qualified mechanic to diagnose and rectify any issues.
Loose or corroded electrical connections: Loose or corroded electrical connections can disrupt the flow of electricity, leading to a loss of power when additional electrical loads are applied. Inspect the battery terminals, wiring connections, and fuse box for any signs of corrosion, loose connections, or damaged wires. Clean and tighten the connections as necessary.
Wiring issues: Faulty or damaged wiring can cause electrical problems in the motorcycle. A short circuit or an open circuit in the wiring harness can result in power loss when the lights are turned on. Carefully inspect the wiring for any visible damage, pinched wires, or exposed connections. If you're not familiar with electrical systems, it's best to consult a professional to diagnose and repair any wiring issues.
Electrical system overload: If you have installed aftermarket electrical accessories, such as high-powered lights or additional electronic devices, they might be overloading the electrical system. The stock electrical system of the motorcycle may not be able to handle the increased power demands, causing the bike to shut off. Consider removing any aftermarket accessories or consult a professional to ensure the electrical system can support the additional load.
Electrical issues can be complex and require expertise to diagnose and repair. It is recommended to consult a qualified motorcycle mechanic or an electrician with experience in motorcycle electrical systems to properly diagnose and resolve the problem.