What is the reason why the motorcycle cannot start after refueling when it runs out of gas?
4 Answers
Motorcycle cannot start after refueling when it runs out of gas due to spark plug failure, the user can replace the spark plug. Spark plug gap: The gap between the spark plug electrodes has a significant impact on the performance of the spark plug. If the gap is too small, the spark will be weak and prone to carbon buildup and leakage. If the gap is too large, the required breakdown voltage increases, making the engine harder to start, and it is more likely to experience "misfiring" at high speeds. Therefore, the spark plug gap should be appropriate. Generally, the spark plug gap for battery ignition systems is 0.7 to 0.8mm, with some spark plugs having gaps up to 1.0mm or more. Spark plug heat value: The standard for spark plugs often uses heat value to characterize the thermal properties of the spark plug. The heat value of a spark plug indicates the balance between heat absorption and dissipation of the spark plug insulator skirt. The higher the heat value, the stronger the balance between heat absorption and dissipation. Thus, hot-type spark plugs have lower heat values, while cold-type spark plugs have higher heat values. Generally, high-power, high-compression engines use cold-type spark plugs with high heat values; conversely, low-power, low-compression engines use hot-type spark plugs with low heat values.
Last time I ran out of gas while riding my motorcycle, and after finally refueling, I couldn't start it no matter how many times I pressed the ignition button. I did some research and found that air might have entered the fuel system, preventing the fuel from reaching the engine in time. This is especially common in older carburetor models, where air bubbles can block the fuel line, requiring multiple throttle presses to flush the fuel through. Sometimes, a wet or worn-out spark plug can also cause ignition failure. If the battery is low on charge, the high power demand during startup makes it even harder to start. It took me over ten minutes of trying before it finally worked. My advice is to be patient after refueling—keep trying the ignition button or check if the fuel filter is clogged. If that doesn’t work, take it to a repair shop to avoid damaging parts by forcing a start. Regular maintenance can help prevent such issues.
When a motorcycle fails to start after refueling following complete fuel depletion, the common cause is air trapped in the fuel line, disrupting fuel delivery. Especially in fuel-injected models, the fuel pump may experience temporary failure due to dry running; carburetor models may require bleeding or throttle-opening to start. Having dealt with similar situations, I recommend first checking that the battery voltage is sufficient, the spark plugs are clean without carbon buildup, and the fuses are intact. Multiple starting attempts can help pump fuel into the system; if ineffective, inspect the fuel pump relay or aging wiring. For safety, operate on level ground to avoid system damage from overheating. Remember, regular fuel system maintenance can minimize such issues.
I've been riding motorcycles for most of my life and have encountered several instances where the engine wouldn't start after refueling when it ran out of gas. Most of the time, it's due to air entering the fuel line, preventing proper fuel flow. My experience is that stepping on the throttle while starting the engine and letting it turn a few more times can pump the fuel in. If that doesn't work, the fuel pump might be damaged or the spark plugs may need replacement. Regular checks on these components can save you trouble; don't rush, be patient, and usually, you can get it sorted.
