What Does a Muffler Do on a Motorcycle? (You Need to Know!)

Motorcycle muffler

Mufflers are one of the most tinkered motorcycle components in aftermarkets. People remove the muffler, add a slip-on to the muffler, make modifications (like straight pipe exhaust) – all sorts of things.

So, what does a muffler do on a motorcycle? The main function of the muffler is to reduce the loud noise and make the motorcycle quieter. It reduces the sound volume drastically and keeps it under 90dB.

That’s a brief overview. Let’s dive more into this muffler thingy, shall we?

What is a muffler?

Muffler on motorcycle exhaust

A muffler, as the name suggests, reduces (muffles) a loud sound. In other words, a muffler lowers the sound decibels.

A muffler in a motorcycle is also called a silencer.

While many will argue that both these parts – a muffler and a silencer are not exactly the same and have some technical differences (the muffler reduces the noise by stopping the flow of sound waves whereas the silencer reduces the noise without stopping the sound waves), that’s not at all true. They are just describing different muffler types.

Both these terms – mufflers and silencers – are often used interchangeably.

So, don’t worry about it. You can mix up the muffler and silencer. No big deal.

The muffler is the end part of the exhaust system. The last and long frustum-shaped pipe, maybe slightly bulky is the muffler portion of the exhaust.

Muffler’s function in a motorcycle

The muffler has two main functions in a motorcycle:

  • reduces loud noise and makes the motorcycle quieter
  • acts as the pathway for the exhaust gases

The primary function of the muffler is to reduce the loud noise and make the motorcycle quieter.

The harmful gas to less harmful gas conversion is done by the catalytic converter installed within the exhaust.

If you ever run your motorcycle without a muffler, the motorcycle will be too noisy. You will hate the noise unless you are one of those high decibel ear-shattering noise lovers.

The muffler helps in reducing the sound volume level drastically.

As for how they do it, mufflers have porous fibers installed within them. What these fibers do is they absorb the pressure waves without blocking the exhaust flow. As the flow continues across the fiber material, the sound volume keeps decreasing.

After absorbing the energy from these exhaust gases, the fibers convert this energy into heat and radiate the heat through the muffler’s outer cover.

I know, it’s a lot of info dump. I am going to stop here. If you want to dig deep into how a muffler works, you can check out the video below.

One last thing. A good muffler not only reduces the sound levels but also ensures the output sound from the exhaust is bearable. This includes adjusting the sound frequencies as well.

Can you ride a motorcycle with no muffler?

Muffler

You can ride a motorcycle with no muffler. But, the noise levels will be too high. Without a muffler, the motorcycle will be too noisy.

Most states and nations have emission and noise standards. So you might run the risk of violating these standards if you ride a motorcycle with no muffler.

While the exact decibel range varies according to the region, the Motor Vehicle (MV) rule book specifies that the maximum sound permissible for motorcycles ranges from 80-91dB. 

If you are riding your motorcycle without a muffler, the noise levels can go as high as 120-130dB. Depending on the motorcycle make and model of course.

That’s why make sure you are not violating any regulations when you are removing the muffler from your motorcycle.

In addition, a motorcycle without a muffler can also face exhaust overheating and backfire problems.

Most straight-pipe exhaust motorcycles have sound and emission problems, overheating, and backfire issues.

So, it is not advised to ride a motorcycle with no muffler in it.

Does the muffler affect engine performance?

Motorcycle Exhaust

Not really.

The muffler does not have a significant impact on engine performance.

Whether you have a muffler or not, the engine will perform. There is no horsepower boost you will get without the muffler. And neither with the muffler.

Sure, someone can argue that by removing the muffler, you are reducing the exhaust weight. The motorcycle is lighter now. So the engine will give better acceleration?

I mean, maybe it does, I am not sure. But that’s how you want to improve your engine performance?

Come on. By that logic, you should start removing each and every part that you don’t appreciate.

The kickstart, you don’t need it. Your self-starter works fine. Why not remove it to make the motorcycle lighter and have greater acceleration?

Oil filter, you have added clean engine oil recently. Remove it. Light weight, higher acceleration right?

Any additional accessories like engine guard, hazard lights, etc. Remove them too.

I hope you get the idea.

It makes no sense to remove a component just to make the motorcycle lighter and have higher acceleration.

And muffler is no exception. Don’t remove for the sake of some unverified claims of improved power or acceleration.

Other exhaust parts

Here is a brief about other exhaust parts apart from the muffler. For a more in-depth view, you can check out our post on motorcycle exhaust parts.

Headers

The exhaust gas from the engine enters these pipes. These pipes move along the engine and release those gases into the collector. It also helps in reducing the backpressure.

Collectors

Collects the gas from the header pipes. Here the conversion of harmful gases and noise reduction (to some extent) happens.

Catalytic Converters

These are housed inside the collectors and inside the connector pipes that connect the header and the collector in a Four into One (or in a Four into Two) exhaust. They convert harmful gases like CO into less harmful CO2.

Oxygen Sensors

These are located near the collector. They sense the amount of oxygen present in the exhaust and send feedback to the engine whether it is using more or less fuel.

Butterfly Valve

Just before the muffler, there is a servo-controlled valve that regulates the backpressure as well as noise.

Bafflers or Silencers

These are components that regulate the noise and backpressure. They are housed inside the muffler.