Motorcycle Exhaust TOO Loud? 8 Reasons (Explained)

Maybe your motorcycle exhaust used to purr like a kitten but somehow developed a louder, more aggressive exhaust tone.

Or maybe you are tired of your neighbors plugging their ears and rolling their eyes when you rip in and out of your driveway or building complex.

Either way, you’ve come to the right place – this article lists the most common reasons why a motorcycle exhaust is too loud and how to solve the problem.

Here are 8 reasons to consider:

1. The Size of Your Motorcycle’s Muffler

The first factor to consider is how loud your motorcycle’s pipes are. As the name implies, a muffler is a component responsible for reducing a vehicle’s engine noise.

A more oversized muffler makes for less noise due to their greater capacity for noise reduction than a small muffler. Therefore, while you might assume a smaller vehicle, like a motorcycle, naturally produces less noise, it works the opposite way.

Motorcycle mufflers are much smaller than car mufflers. They have a smaller capacity for noise reduction, which makes them louder than cars by default.

Motorcycle mufflers are designed to reduce noise levels while allowing optimal engine performance. A muffler functions by converting the engine’s sound waves into heat energy to reduce the amount of sound an engine emits.

The larger the muffler, the more sound waves it absorbs as it has more space to store the heat energy. However, motorcycles don’t have the space to accommodate the type of mufflers cars equip.

If you’re wondering why your motorcycle is louder than a car, motorcycles stock much smaller, much less effective mufflers than the large-scale noise-converters used on larger vehicles. 

2. Short or Damaged Exhaust Pipes

Also, the length of your motorcycle’s exhaust pipes can affect the noise level of your motorcycle’s engine.

A motorcycle’s exhaust pipes are designed to reduce the noise emitted from the engine. They do this by muffling and cooling the exhaust gasses that flow from your engine during combustion and revving.

The longer your motorcycle pipes are, the more time and space the gasses have to accumulate and dissipate before shooting out of your pipes. Therefore, the longer your motorcycle pipes are, the less noise your engine and exhaust will be.

Conversely, shorter exhaust pipes let the gasses shoot out rapidly before the gasses can disperse, making the release more pressurized and much louder.

If you recently put shorter pipes on your motorcycle and removed the exhaust tips or the baffles, your motorcycle will be noticeably louder than before.

Furthermore, if your pipes are cracked, punctured, or corroded with holes, the gasses will force their way out, and the bike will be louder.

Here are notes to consider:

• Exhaust tips are stuck on the end of the pipe to add time for the gasses to disperse and cool before they exit.
• Baffles are chambers in your motorcycle’s pipes designed to absorb and cancel out any sound waves left or right before the gasses exit.

Thus, if you want to make your motorcycle exhaust quieter, install longer pipes with baffles and exhaust tips in place.

On the other hand, if you want a louder exhaust system, opt for shorter exhaust pipes with fewer baffle chambers.

3. Lack of Time for Air and Exhaust to Slow Down

Continuing on the previous topic, this section directly relates to the length of your pipes but seeks to go deeper into the science of the situation.

A motorcycle’s exhaust is too loud because short, cut, or damaged pipes don’t allow the air and exhaust gasses enough time or space to slow down before they exit the pipes.

In addition to temperature and pressurization, the noise levels of your motorcycle’s exhaust system depend on the speed of the air and exhaust fumes flowing through it.

The faster the air and exhaust move, the more force they accumulate and the louder they sound when exiting.

Moreover, a motorcycle engine generates pressurized pulses of air and exhaust fumes as a byproduct of operation, and these byproducts are removed via the exhaust pipes.

If the pipes are too short, narrow, or straight, they won’t provide enough time or space for the air and exhaust fumes to slow down, cool off, and lose energy. This often results in a loud, growling exhaust sound.

Also, a proper exhaust system should include long, wide pipes with curves to extend the exhaust fumes’ cooling time. This is because the resistance and turbulence of the increase in exhaust travel time dissipate the energy and cool the temperature.

If you bought your motorcycle used, the previous owner might have cut the pipes or added short, narrow straight pipes to make their moto louder.

If short pipes or reduced exhaust-cooling time and space is why your motorcycle exhaust is too loud, you’ve likely experienced engine performance issues like backfiring and misfiring.

Make sure you also read about why motorcycle makes whinning noise.

4. No Engine Shields; Open Motor

Another factor that intensifies the noise level of a motorcycle’s exhaust system is the lack of an engine compartment encasing, such as a car hood, which covers the engine and dampens the noise.

Unlike cars and trucks, motorcycles don’t have a metal or alloy shell to muffle the engine noise. While sealed-cylinder engines are becoming more popular on bikes, they’re still exposed to the atmosphere.

• The motorcycle’s engine and exhaust system are open and located right underneath the rider’s seat, making their sound waves more audible.

Moreover, the combustion process of a motorcycle engine includes rotating and oscillating valves, pistons, and camshafts, all of which produce noise. These noises aren’t muffled without an engine compartment encasing, making a motorcycle’s exhaust system loud by default.

One way to reduce the engine and exhaust noise of a motorcycle that’s too loud is to install engine shields, sometimes called heat shields.

Engine shields attach to your motorcycle’s frame and cover some parts of the engine exhaust. They protect the engine from dirt and debris, protecting the rider’s legs from heat, and absorbing some of the engine noise before it reaches the rider’s ears.

5. Damaged Pipe Headers Need to Be Replaced

Pipe headers are the exhaust system component connecting your engine cylinders to your exhaust pipes. They are typically fabricated from metal and include bends and curves based on the particular engine layout of the motorcycle. So they fit correctly.

Mind you, corrosion, rust, collision damage, or engine overheating can crack, dent, or puncture the headers. They can create leaks and holes and allowing hot, pressurized exhaust gases to escape before it even reaches the bike’s pipes.

The release of hot gasses increases the ambient noise of your motorcycle’s exhaust system and reduces engine performance and fuel efficiency.

It is important to note that damaged Pipe headers should be repaired or replaced as soon as possible. If you need to reduce the noise level of your motorcycle exhaust asap, you can use exhaust tape or epoxy to seal the leak in your headers.

That said, these methods are only temporary and may not last long. The permanent solution will be to replace your headers with new ones, preferably from the original manufacturer, designed to fit your specific make and year model motto.

You’ll need to adjust your carburetor/fuel injection to ensure a proper air-to-fuel ratio for ideal engine performance and to avoid overheating.

6. Dirty Exhaust Packing

Exhaust packing is typically fiberglass, steel wool, or ceramic fibers, stuffed between the inner and outer walls of your motorcycle’s muffler.

It serves two primary purposes – to reduce the noise level of the exhaust system by absorbing some of the sound waves, and insulating the exhaust system from the hot gasses, extending the life of the exhaust.

Over time, the exhaust packing gets dirty, wet, and scorched from exposure to moisture, carbon deposits, and hot oil.

The wear and tear incurred by your exhaust packing from routine use reduce your engine performance and make your exhaust system louder until the filling is replaced.

• To replace your exhaust packing, remove your muffler from your exhaust system and open it up.
• Next, remove the worn packing and clean the inside of the muffler free of dirt, grime, carbon, and moisture.
• Repack the muffler following instructions for your motorcycle’s exhaust system.
• Reassemble the mute and reinstall your exhaust system.

You might also want to check out our post on why motor won’t start but backfires.

7. Aftermarket Exhaust System

An aftermarket exhaust system can make a motorcycle too loud. This happens when you change the muffler’s design, size, or material and exhaust pipe specs.

Some aftermarket exhaust systems equip fewer baffles, chambers, or sound-absorbing materials than the factory system. This makes them less efficient for your engine design and increases the noise your exhaust system makes.

If your motorcycle exhaust system seems louder than it should and you purchased your bike used, it could be that the previous owner changed the pipes, mufflers, headers, or whole system, either for more exhaust pressure or because they wanted their bike to be louder.

Aftermarket exhaust systems often use shorter, narrower straight pipes to lessen the back pressure resistance of your exhaust flow.

This increases the speed and volume of the gasses. It also amplifies your throttle response and acceleration while increasing the sound waves protected from your pipes.

Read Next: 10 Motorcycle Noises Solved (Explained For Beginners)

8. Tampering with EPA-Regulated Factory Exhaust System

Tampering with your EPA-regulated factory exhaust system can cause engine and exhaust performance problems and legal issues. It could also make your motorcycle exhaust too loud.

The EPA regulates the factory exhaust systems of motorcycles are fitted to ensure that they meet the emission standards and noise limits enforced by the Clean Air Act.

Tampering with the factory exhaust system is defined as changing, removing, or disabling any part or component that affects the emissions or noise of the motorcycle, including the catalytic converter, the oxygen sensor, the muffler, the exhaust pipes, and the engine calibration.

Tampering with the factory exhaust system can cause several problems, such as:

Engine and exhaust performance problems

Tampering can affect the air-fuel ratio, the combustion process, the back pressure, and the temperature of the engine and exhaust system. This could reduce performance and increase the risk of engine damage, overheating, backfiring, or stalling.

An increase in exhaust noise

Tampering can make the motorcycle exhaust too loud by removing or altering the muffler or other noise-reducing components, creating a nuisance for others and violating local noise ordinances.

Legal issues

Moreover, tampering with your exhaust is illegal under the Clean Air Act and can subject the violator to civil penalties.

Sources:

Motorcycle Exhausts 101 – RevZilla

National Enforcement and Compliance Initiative: Stopping Aftermarket Defeat Devices for Vehicles and Engines | US EPA

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