Why is the engine of a scooter so loud?
2 Answers
It is recommended to check whether the valve clearance is too large, and whether the valve rocker arm and camshaft are worn, among other possible causes. Below is a related introduction to scooters: Introduction: A scooter refers to a motorcycle with a wide footboard between the seat and the handlebars, allowing the rider to comfortably place their feet on it, as if sitting on a chair, without needing to straddle the bike like other motorcycles. Clutch: Scooters are mostly equipped with continuously variable transmission (CVT) automatic clutches, similar to electric mopeds, with no gear design. After starting, you only need to twist the throttle to move, and releasing the throttle will automatically and gradually slow down until stopping. Additionally, the wheels of scooters are smaller than those of other motorcycles, and the transmission system is mostly belt-driven, commonly referred to as a "step-through" or "ladies'" motorcycle.
Once my scooter's engine suddenly became extremely loud, and I thought it was a racing sound effect. Upon closer inspection, it turned out the exhaust muffler had aged and developed a leak—when the soundproofing material inside falls off, it amplifies the noise. Also, the chain had become loose, making a rattling sound while riding, which was quite alarming. Worn piston rings in the engine are another common cause, and loose oil seals can worsen the friction noise. If the air filter is clogged, restricting airflow, the engine struggles to work as if holding its breath, naturally becoming noisier. If a new bike is already loud, it might be due to a poorly designed aftermarket exhaust pipe with bad backpressure and severe resonance. I recommend checking the oil level before each ride and stopping immediately if you notice unusual sounds—don't push it and risk major damage. It's best to ask someone familiar with bikes to help pinpoint the source of the noise to avoid wasting money on unnecessary repairs.
