So, you belong to that group of riders who prefer their motorcycles to be quiet.
(Frankly, not everyone likes an overdose of unwanted attention.)
And perhaps you are wondering about how to make the motorcycle quieter.
Then you are in the right place. We are about the discuss how to make a motorcycle quieter, without losing any performance.
Let’s get started.
Why Are Motorcycles So Loud?
The first question that comes to mind is, what makes a motorcycle exhaust howl like a banshee on stimulants?
For example, consider a Harley. They are already on the louder end of the scale as they leave the assembly line. But with the addition of an aftermarket exhaust system, they can get even louder.
And surely there are the squids who have not much control over the mechanical aspects of their bikes.
But there are some reasons that make motorcycle exhaust naturally louder.
Firstly, motorcycle engines are small and compact to reduce weight. The engine compartment is relatively thinner and open to the atmosphere. So, they do not have sufficient sound shielding that can fully prevent the noise of the combustion from coming out.
It goes without saying, the higher the RPM of a motorcycle, the louder it will get.
Next, motorcycle exhaust pipes are shorter in length and narrower. In most cases, the exhaust pipes are around 3 feet in length. Compare that to automobile exhaust pipes that are between 8 to 16 feet in length.
You get the picture.
Longer exhaust pipes allow the exhaust gases to lose more energy. As these gases travel through the pipe, they bounce around and the sound levels come down.
Since motorcycle exhaust pipes are shorter, the exhaust gases come out with higher velocity and more noise.
Lastly, it comes to the muffler design. Motorcycle mufflers are smaller in size and the baffles they use don’t absorb much energy. If you look at cars, the mufflers mostly contain a large resonance-type box that has multiple chambers to reduce the noise.
Now, many bikers will argue that loud bikes are safer. But honestly, there’s no specific evidence to support that theory.
How to Make Motorcycle Exhaust Quieter?
Thankfully, there are some ways that will help you to quieten your bike (and earn the gratitude of your neighbors for not jarring their molars in the middle of the night).
Here are some ways to do it:
The first thing you can do is to check the exhaust system for any leaks or holes. This damage can cause more sound to leak out of the pipe. If you have a second-hand bike, the chances of holes in the pipe are higher.
Now, if your exhaust pipe is as rusty as a pirate’s ancient treasure chest, you need to clean it up to locate the holes. Small holes can be easily fixed with exhaust tape.
That sounds super easy.
Now, hold on. There can be larger holes in the pipe too!
To repair them, you will need to buy a special epoxy stick or an exhaust patch kit. Apply it as per the instructions, and wait for a few hours before starting the bike.
If it still doesn’t work, then it’s time to replace the pipes. You can take the help of an experienced technician to get custom-designed longer exhaust pipes that will cut down the noise.
Upgrading The Mufflers
The next step you can take is replacing the teeny-weeny muffler with a more robust one.
In general, most stock mufflers are compliant with the noise regulations set by EPA (Environment Protection Agency). But you can add mufflers with more advanced features like special bafflers, resonators, or materials like fiberglass.
Personally, I have seen chambered mufflers perform better than “straight-through” mufflers. Pick a dual-chambered design that cuts down the noise more effectively.
Another great option is using a resonator muffler. These designs come with a layer of fiberglass that can absorb sound effectively.
Obviously, this is a task that will need the help of a professional. Best NOT make it a DIY project.
Note, this will also be an expensive option. On the other hand, it will deliver great results.
One more thing…
Don’t forget to install the catalytic converter with the muffler. Other than minimizing emissions, they also reduce the sound levels to some extent.
Use A Silencer
Silencers come with a special structure that cuts down the noise output. It narrows down the outlet hole and makes the exhaust gases quieter.
Before you buy a silencer, make sure it has the correct diameter to fit the exhaust pipe. Ideally, it should have a slightly smaller diameter than the inner diameter of the exhaust. If it’s longer in length, you can cut it down to the right size.
Installing the silencer is an easy task that you can easily manage.
And if you already have a silencer installed, think about repacking it with some special material. These are usually glass fiber yarns that are placed between the inner tube and outer casing of the silencer.
Basically, packing the silencer isn’t a difficult task. But if you’re not confident about putting on your gloves and performing the surgery, get the help of an expert.
Use an Exhaust Wrap
Admittedly, exhaust wraps aren’t designed to reduce noise. But using a top-grade exhaust warp can reduce the noise by absorbing it to some extent. More specifically, they absorb higher frequencies more effectively.
Also, they are an affordable option. And you can apply them on your own with the supplied instructions. But, check the pros and cons of exhaust wrap before you proceed.
Switch Back To The Stock Exhaust
Let’s assume you are planning to leave your noisy days behind after running on an aftermarket exhaust system for years. Time to switch back to the good old stock exhaust the manufacturer designed for your motorcycle and cut the noise.
Aftermarket systems can deliver a noise output above 100 dB. Chances are the old system will cut down the noise to less than 80 dB. That’s not exactly super quiet, but definitely a significant drop. At the same time, you won’t have to worry about any loss in performance.
Frequently Asked Questions
How to make an aftermarket exhaust quieter?
An aftermarket exhaust can be made quieter by adding a silencer or by wrapping up the pipes.
How to make straight pipes quieter in a motorcycle?
The straight pipes can be made quieter by replacing the muffler and installing a better one. You can also add a silencer or try wrapping up the pipes.
Is it illegal to have a loud exhaust?
The legal limits on motorcycle exhaust noise vary from state to state. Some states have no limits, while others need motorcycles to have an adequate muffler. Some others have a specific noise limit based on the year of manufacturing of the motorcycle.