Why are motorcycles so much louder than cars or buses?

Actually, they aren't. We have this stupid idea that noise equals power. Harley riders are the worst at this. They remove the mufflers completely, or buy aftermarket pipes that are considerably louder than the stock exhaust. read more

The power band of a motorcycle engine is often at a higher RPM than that of a car engine, so the motorcycle engine will run consistently faster, and therefore louder. A 1.4L car engine would be louder than a 600cc sportbike engine, for example, if they were running at the same RPM. read more

Other than mufflers. Motorcycles have the engine exposed so all the noise it makes go directly into the air around it. Cars keep the engine enclosed within the body so a lot of the noise gets absorbed by the body of the car. Motorcycles usually have thinner cylinder walls due to their smaller size, so the boom noises from inside escape easier. read more