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A dirt bike already produces a large amount of noise, but this can be exacerbated by a number of factors. The good news is you can affect most of these factors to reduce the volume of noise and not end up permanently damaging your eardrum.
To make a dirt bike quieter, you need to buy a new muffler, silencer, spark plug arrestor, and also ensure that there are no maintenance problems with your bike that could be causing unnatural noises.
If you follow these 12 expert tips, your dirt bike will be transformed into a much quieter beast. Keep reading for an informed guide on why your dirt bike is so loud and how to affect decibel volume.
- 1 Buy a New Muffler
- 2 Buy a Muffler Silencer
- 3 Clean Your Exhaust Pipes
- 4 Check for Exhaust Leaks
- 5 Ensure Complete Combustion
- 6 Wrap Your Exhaust Pipe
- 7 Get New Pipes
- 8 Get a Spark Arrestor
- 9 Ensure You Have a Closed Air Box
- 10 Tighten Nuts and Bolts
- 11 Use the Correct Oil for Gearbox
- 12 Get Your Bike Checked Out
- 13 Conclusion
Buy a New Muffler
A muffler is responsible for keeping your dirt bike’s noise output at manageable levels. Modern bikes come with factory-installed mufflers due to the enforcement of the USA Noise Control Act, which mandates that noise caused by motorcycles and other vehicles can only reach a certain amount of decibels.
Although there might be no performance issues with your muffler, it is important to remember that all companies value profit. They will not be giving you a premium quality muffler for your dirt bike because that will cause a spike in prices, and fewer people buy from them. As a result, you should be buying and installing a new, better-quality muffler on your dirt bike if you’re really serious about reducing noise.
The muffler that you should be buying needs to align with your bike specifications. Here are some things that you need to look out for when buying a new muffler:
- Type of exhaust system. Depending on whether you have a single or dual exhaust system, you will need to change the number of inlets that you need on your muffler.
- Exhaust pipe diameter. You will usually need to match your inlets, and in some cases, outlets with the exhaust pipe diameter.
- Vehicle specifications. You will need to take the exterior specifications of your vehicle so that you can buy the right muffler. The proper length and casing size mean that you will be able to install your new muffler easily and with proper clamping while allowing it to fit in the undercarriage.
The muffler type that will give you the biggest bang for your buck is called a “slip-on” muffler. As the name suggests, it is easily installed while effectively reducing noise. However, this comes at the cost of reducing horsepower and torque.
If you want a dirt bike that will go fast while still maintaining a lack of noise, you can go with a full system exhaust. This replaces everything – the header, midpipe, and muffler. On the other hand, a full system exhaust is much more expensive than a slip-on and does not reduce noise any further, instead of optimizing horsepower and speed.
Here are the three options of mufflers that you can pick from:
Chambered mufflers have a number of chambers with different configurations for sound waves to bounce off of. As these soundwaves bump into each other, they cancel each other out and reduce overall noise. They also contain sound-canceling plates called “baffles” within. The sound produced by chambered mufflers is akin to a throaty purr, with this consistent tone guaranteed because the materials making up the packing will never blow out.
A turbo muffler is constructed in an S shape and uses less than 3 perforated tubes. Although the design is somewhat restrictive compared to your other options, it is still the quietest of all three types of mufflers, making it a great step up from a stock muffler.
This kind of muffler uses a single, perforated tube and has a fiberglass or steel wood packing, encased in an aluminum shell. Quieter mufflers have a more angled tube while louder mufflers have a straighter tube. These kinds of mufflers are the loudest of all three because the soundwaves have a direct path out of the exhaust resulting in the maximum amount of energy being transmitted out of the dirt bike.
When you’re buying your new muffler, try to make it a turbo muffler or a chambered muffler that sounds quieter than stock if you can find one. Never buy a glasspack muffler because it will not help with noise reduction.
You might also want to head down to an actual repair shop to see how well it works and if it actually fits your dirt bike. When you’re buying online, practice caution, and do not buy from sites like Amazon. Instead, opt for the mufflers found on the official websites sold by different brands. That way, you know that the quality of the parts you buy are not cheap and will actually work.
Buy a Muffler Silencer
A silencer is an additional method to reduce the amount of noise that is produced by your muffler. It works by reducing the size of the exhaust hole to remove additional noise while still allowing combustion and the emission of gases from your dirt bike.
Instead of a loud sound that rings and retains the same intensity from a few meters away, a silencer focalizes the noise and ensures that the output from even a few meters away is much decreased.
If you want to buy a silencer, as with a muffler, you need to know the specifications of your exhaust pipe because you will be inserting it inside the pipe. Instead of buying a silencer online, you should go down to a dirt bike shop and ensure that it fits your bike before buying it. The silencer’s outer diameter needs to be slightly smaller than that of the inner diameter of your exhaust pipe.
Clean Your Exhaust Pipes
Dirty exhaust packing will emit a loud, shrill noise, which is significantly more unpleasant than loud, deeper tones. Beyond the noise emitted, the machine will also become less efficient, with reduced horsepower and dark smoke being emitted from the exhaust pipe.
You should aim to replace your packing before the situation gets too bad – for an average rider, that’s every 20 hours of motorcycle use. On the other hand, if you’re not riding on rougher terrains often, your packing will probably last much longer.
However, depending on your bike settings, it can unwittingly last for a much shorter amount of time. For example, if you put the jetting on lean, your bike packing might be blown much more often than if you hadn’t. Keep in mind that bike settings also affect how long the packing lasts.
You can aim to replace your packing yourself using this guide, or you can head down to your local dirt bike shop for repairs.
Check for Exhaust Leaks
If your bike is suddenly emitting significantly more noise, check for exhaust air leaks. You should look along the body of the silencer in the head to look for any cracks and dents.
Exhaust leaks are either caused by rust or wear and tear. Even a very small leak can significantly impact the amount of noise coming from your dirt bike, so ensure that the only openings on your bike are the one designated opening at the very end.
To patch up a leak, re-weld and tighten the surrounding materials. If that doesn’t work, you will need to purchase some high-temperature silicone to fix it.
If the leak is caused by rust on your bike, it would be better for you to clean it before you start catching the bike up. You can clean it by soaking it with vinegar for a few hours and then wiping it all off.
Ensure Complete Combustion
In engines, a process called combustion takes place, with fuel being burnt to provide energy to the motorcycle so that it will work. As air is only made up of 21% oxygen and combustion requires oxygen to take place, a great amount of air is needed for a conducive combustion environment.
When combustion occurs, depending on the type of fuel that is being used, hydrocarbons of different ratios are being used in a chemical reaction with oxygen in the air to produce the energy that keeps your motorcycle running. However, when the amount of oxygen and, by default, the air is insufficient, incomplete combustion will take place.
When incomplete combustion happens in your engine, carbon monoxide is produced, and a noisy ‘popping’ sound occurs. In order to facilitate complete combustion, you can use a mushroom head air filter, which increases air intake by 50%. Even if your machine already comes with a mushroom head air filter, try looking for a better quality aftermarket one to reduce noise.
Proper combustion is important because not only will it make your dirt bike noisier, but it will also cause a decrease in performance. It is better to have a higher air to fuel ratio than a lower one.
Wrap Your Exhaust Pipe
The wrap works by reducing vibrations and frequencies of sound waves and thus decreasing the amount of sound produced. It is composed of titanium and is usually put on the inside and outside of the muffler. If you add fiberglass, it is possible to reduce up to 80% of the noise.
Wrapping your exhaust pipes also has a number of other benefits, like preventing the discoloration of the pipes and potentially increasing horsepower.
However, the wrapping will wear off in approximately six months, so if you’re truly serious about wanting to reduce noise generated from your dirt bike, you will need to go through the hassle of re-wrapping every half-year.
After you’ve wrapped your pipes, try and observe if there seem to have been any negative effects on your bike over time. Some say that wrapping your pipes in the case of certain bikes can cause overheating and reduce performance, so observe your bike closely to ensure that this isn’t happening to your particular bike.
Get New Pipes
Sometimes, there’s nothing that can be done to reduce the noise but get new pipes for your motorcycle. This could be necessary for a number of reasons – either your pipes could be irreparably damaged, or if you bought an older model that uses shorter pipes, the noise level is deafening.
If your bike has a dual exhaust system, you should install cross pipes. The mixing of sound from the two systems greatly reduces noise. You can use the y-pipe and h-pipe designs.
Otherwise, look for angled aftermarket pipes to reduce those decibels.
Get a Spark Arrestor
The primary function of a spark arrestor is to remove sparks before they cause any problems with the equipment in your motorcycle. It is legally mandated in some states, especially on trails, to prevent fires from occurring.
Despite this, a spark arrestor is useful in reducing noise. It can reduce sound by up to 10 decibels, and when used in conjunction with a muffler, will make your dirt bike quieter. Most motorbikes do not come with an inbuilt spark arrestor, so you will likely have to purchase one.
Unlike mufflers, which have needed to be specially designed so that they do not affect performance, a spark arrestor will not impact the power of a dirt bike in any way.
Ensure You Have a Closed Air Box
Not all of the air in your motorcycle will be coming out from the exhaust. If you’ve recently decided to vent out the air box, or if you have removed the lid to clean it, you might have forgotten to close it back up. Ensure that your airbox is always closed. Otherwise, your bike will be producing a lot of unwanted sounds.
Tighten Nuts and Bolts
Some of the noises that you hear might just be from vibrating parts when your dirt bike goes at high speeds. Those strange ticking and clunking sounds that you hear could just be the spring vibrating or from the footpegs knocking into each other.
If you’ve been using your bike for a long time, this is a phenomenon that you will experience, especially if you like to ride fast. The wear and tear are to be expected with time – you just need to weld everything back into place and fasten it properly. In addition to welding, you can also use lock washers – tools that are specially designed to prevent fasteners from slipping upon intense vibration.
These heavy-duty Loctite Threadlockers – a type of epoxy, is perfect for preventing fasteners from slipping, but it can easily be removed with handheld tools.
On the other hand, if noise doesn’t stop coming from your bike even after tightening, go to a garage and get your bike looked at because there is probably something wrong with your engine.
Use the Correct Oil for Gearbox
A less common place to search for noise is the gearbox. If you do not use the right viscosity of oil in the necessary amounts, your gearbox can produce all types of strange noises. Look through your manufacturer’s recommendations and ascertain, which kind of oil is appropriate for your specific gearbox.
If your manufacturer has not given you any specifications regarding the type of oil that you should be using, but just general instructions, that could be causing the problems with both noise and performance in your gearbox.
As this is a highly complicated subject, it is better to look for advice from an expert instead of trying to DIY. Head down to your local dirt bike shop or call nearby services to get some counsel regarding specifications.
When you find out the correct type of oil you should be using, be sure to change it often.
Get Your Bike Checked Out
If none of the tips above have helped you reduce the noise level, there is something fundamentally wrong with your bike. Go to the nearest local repair shop and look into it further because there is a possibility that you have gotten a faulty model from the company.
Alternatively, another reason why none of the tips might be working for you is that you tried to DIY them yourself and implemented it incorrectly, in which case, it would also be appropriate to head down to a repair shop and get your dirt bike looked at.
Having a dirt bike is really fun, but it is also necessary to remember the responsibilities that come along with the upkeep of the bike. Because you’ll likely be using the dirt bike on trails, it is imperative to try to keep the volume as low as possible so as not to scare or threaten the natural wildlife living around the trails.
Having a quieter bike does not mean changing the tone and sound of the noise produced, so you don’t need to worry about your motorcycle sounding different.
If you’re really serious about wanting to have a quiet dirt bike, it is best to get an electric bike. These produce almost no sound and can be ridden anytime, anywhere, without disturbing the peace and quiet.