What is the reason why the electric start of a motorcycle cannot ignite but the kick start can?
5 Answers
The electric start of a motorcycle failing to ignite while the kick start works may indicate a problem with the motorcycle's battery, or it could be due to cold weather causing a decrease in engine oil performance, leading to insufficient cylinder pressure. Below are some common motorcycle fault-related introductions: 1. Blue smoke from the exhaust pipe: First, check if the engine oil level is too high, as an excessively high oil level can cause oil to rise. When checking the oil level, do not do so immediately after the engine stops; wait for about 10 minutes after shutdown before checking. 2. Black smoke from the exhaust pipe: Check the concentration of the air-fuel mixture. After noticing this symptom, first inspect the carburetor air valve. After the engine shuts down, observe the main nozzle from the carburetor. If there is oil flowing or dripping, it indicates that the float chamber oil level is too high. Adjust by appropriately bending the float's tongue upwards or adding suitable shims under the needle valve seat. 3. White smoke from the exhaust pipe: White smoke from the motorcycle's exhaust pipe is often caused by water vapor in the fuel, cylinder, or muffler. 4. Insufficient power: This situation is mostly due to aging piston rings causing poor sealing, valves not closing tightly, or a clogged carburetor.
This situation is actually quite common, mainly caused by electrical system issues. Insufficient battery voltage or aging is the most frequent cause - motorcycle electric starters require high current to drive the motor, and a weak battery won't be able to turn it. Poor contact in the starter button or loose wiring connections could also be the culprit, especially after riding in rainy weather when oxidation tends to occur. Another possibility is a faulty relay, which is responsible for conducting high current during electric starting - if it's broken, the current won't pass through. Finally, the starter motor itself might have problems, like worn carbon brushes or a seized rotor. I've encountered this several times when repairing bikes myself. The best approach is to first test the battery voltage, then check all wiring connections for looseness or oxidation. If everything seems normal, you'll need to disassemble and inspect the starter motor. For older motorcycles, special attention should be paid to aging wiring issues.
I've been riding motorcycles for over a decade, and this kind of electric start failure is all too common. Eighty percent of the time it's a dead battery – either the capacity drops after prolonged use or it loses charge from sitting idle for too long. You can clearly feel the starter motor struggling when cranking. Another simple possibility is dirty contacts on the start button, where dust and grime cause poor connections. Loose wiring connections can also prevent power from getting through, especially after riding on bumpy roads. If you don't hear the relay click when turning the key, it's probably faulty. The most annoying issue is when the starter motor's coils burn out, which requires professional tools to diagnose. So my advice is to first try charging the battery or jump-starting it. If that doesn't work, check and clean the start button. These are things you can do yourself with basic tools, saving on repair costs. Of course, more complex motor issues still require a mechanic's expertise.
My old motorcycle had this exact issue. The fact that it can be kick-started proves the engine and ignition system are fine—the problem definitely lies in the electrical components. The most common culprit is an aging battery; after 3-5 years, it can't hold a charge properly. You can diagnose by sound during startup: if the starter motor hums but won't turn over, it's likely low power; complete silence may indicate wiring contact issues—especially after washing when connectors get rusty from water exposure. Also check if any fuses are blown, though that's rarer. If all else fails, inspect the carbon brush wear inside the starter motor. Pro tip: disconnect the battery before long winter storage to prevent discharge damage. Modern lithium batteries last longer but still require regular charging maintenance.
The motorcycle's electric start system requires a complete current circuit. The fact that the kick start can start the engine proves that both the magneto and CDI ignition are functioning properly, so the issue is limited to the battery circuit. Starting from the battery positive terminal, the current passes through the starter button controlling the relay coil, and then the relay contacts connect to the starter motor. Any abnormality along this entire path can cause a malfunction. For example, if the battery voltage drops below 10V, it won't be able to drive the motor; oxidized wiring increases resistance, and burnt relay contacts affect conductivity. The most easily overlooked issue is loose grounding connections, which prevent the current from completing the circuit. It's recommended to use a multimeter to troubleshoot from simple to complex: first, measure the battery's static voltage (normal above 12.6V), then measure the voltage drop at the motor terminal during startup. If the drop exceeds 2V, check the wiring connections, and finally, disassemble and inspect the motor's internal components.
