Why does the motorcycle not start and the relay makes noise?
4 Answers
If the circuit breaker makes a beeping sound, the most likely cause is a depleted battery or corrosion on the battery terminals leading to excessive resistance. If the battery is ruled out, check whether the starter relay is faulty. You can directly connect the two terminal posts or the two thick wires of the starter relay. Another possibility is a fault in the starter motor, such as worn carbon brushes or commutators inside the motor, or excessive dirt—cleaning with fine sandpaper may help. The starter motor's coil could also be burnt out, requiring replacement. The electric start of a motorcycle consumes a significant amount of power, while the headlight and horn use much less, so normal operation of the lights and horn does not guarantee sufficient battery power for the electric start. Below is relevant information: Introduction: A relay (English name: relay) is an electrical control device that causes a predetermined step change in the controlled quantity in the electrical output circuit when the input quantity changes to meet specified requirements. It establishes an interactive relationship between the control system (also known as the input circuit) and the controlled system (also known as the output circuit). Typically used in automated control circuits, it functions as an 'automatic switch' that uses a small current to control a larger current. It plays roles such as automatic regulation, safety protection, and circuit switching in electrical circuits. Applications: Relays are automatic switching elements with isolation functions, widely used in remote control, telemetry, communication, automatic control, mechatronics, and power electronic equipment, making them one of the most important control components.
Last time when my motorcycle failed to start but the relay was clicking, I guessed it might be due to insufficient battery power. After riding for several years, battery aging is quite common - the voltage drops below 10V during startup, causing the relay to click but fail to conduct the main circuit. I usually first test the battery with a voltmeter; if it's below 12V, I'll charge it or replace it rather than forcing startup to avoid damaging components. Oxidized relay contacts are another factor - disassembling and gently sanding them with sandpaper can improve contact. For prevention, check battery lifespan and maintain the relay unit before winter, regularly monitor electrolyte levels to avoid unexpected breakdowns. If the problem persists, suspect a stuck starter motor and go directly to a professional repair shop instead of wasting time and effort on futile attempts.
From my perspective as an auto mechanic, relay clicking indicates the low-current circuit is functioning properly, but high current cannot pass through, commonly caused by contact erosion or weak battery. Battery aging is the root cause - when static voltage drops below the standard 12.6V, it leads to insufficient starting power; always check battery condition during diagnosis. If relay internal contacts are corroded, replacement is necessary - simple DIY cleaning can serve as temporary solution but professional service is required for permanent fix. Also inspect circuit factors like blown fuses or loose ground wires, using a multimeter to efficiently locate open circuits. For maintenance, regularly replace relays to prevent aging and avoid accelerated damage from humidity during rainy seasons. Starter motor failure is less probable, but if all other components check out, then consider its issues - never compromise safety by forcing startup.
I drive quite cautiously, so I stopped immediately when this issue occurred. The relay clicking but the engine not starting indicates a system abnormality. Continuing to attempt starting could lead to overheating damage, which is unsafe. The best course of action is to have it checked by a professional repair shop—they can quickly diagnose whether it's a battery or relay issue. Regular maintenance like keeping the battery charged and cleaning connection points can prevent such problems. Don't risk DIY attempts to avoid accidents; safety comes first.
