If you’ve spent any kind of time around motorcycles, you’ve no doubt noticed that none of them really sound anything like cars. You might be wondering why that is, considering both cars and motorcycles use internal combustion engines that work largely the same way.
Put simply, there are several common differences between car and motorcycle engines that make them sound different. These differences include their exhaust systems, the number of cylinders they have, the speed at which they rev, and the engine displacement.
Today, we’ll be going over how each of these things affects engine sound and why they make motorcycles sound so different from cars.
Reasons Why Motorcycle sound different than cars
Wonder why motorcycles sound the way they do?
- Exhaust System
- Number of Cylinders
- RPM
- Engine Displacement
Exhaust Systems
Probably the biggest factor that affects engine sound is the exhaust system. On cars, the exhaust system is designed not only to filter out harmful emissions but also to decrease the volume of the engine. They do this through the use of one or more mufflers.
However, cars are only able to have so many mufflers thanks to the length of the exhaust system. Car exhaust systems are usually about 8-12 feet long, so there’s obviously a lot of space along that length to add whatever sound deadening components you need.
In contrast, motorcycle exhaust systems are barely longer than 3 feet in most cases, so there’s just not enough room to add a muffler in most cases. Thus, motorcycle engines often tend to be a lot louder than car engines.
Number of Cylinders
The number of cylinders in an engine also affects how an engine will sound. The vast majority of passenger cars have inline-4 engines, with 6- and 8-cylinder engines being pretty common also.
On the other hand, it’s rare for a motorcycle to have more than four cylinders. Some larger touring bikes like the Honda Goldwing have 6-cylinder engines, but most sportbikes only have 3- or 4-cylinder engines. Harley-Davidson bikes usually only have 2-cylinder engines.
RPM
The engine speed, also known as RPM (revolutions per minute) also affects how an engine sounds. In general, the higher an engine revs, the higher the pitch of the engine sound becomes.
The majority of passenger cars with inline-4 engines typically redline somewhere around 6,000 RPM or so. A sportbike, on the other hand, hits its redline usually somewhere around 10,000 RPM.
Bikes are able to rev so high because their engines are usually pretty small and lightweight, meaning the moving components inside the engine like the pistons aren’t as stressed when moving at high speeds. Because sportbike engines don’t have a lot of torque, it’s necessary to make them rev very high in order to produce enough power to get moving quickly.
Engine Displacement
Engine displacement is the final thing that affects how an engine sounds. This generally doesn’t affect engine sound as much as the other things we’ve mentioned, but it’s still a factor nonetheless.
Typically, the larger your engine displacement is, the deeper the sound of the engine becomes. Most cars these days have 2-liter engines, but the majority of sportbikes have engines that displace 1 liter or less.
Harley-Davidsons have engines ranging in size from 1.7 to 1.8 liters, but again, they typically only use 2-cylinder engines so that makes the most significant difference in how they sound.
