Motorcycle Sounds Like Bubbles? Here’s Why And How To Fix It

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Motorcycles can make a slew of sounds, some good and some not so good. Some sounds may catch you by surprise since you didn’t know a motorcycle could sound like that. One of those sounds may be bubble-like. Don’t worry, you’re not going crazy if you hear this. In fact, it’s common enough that we even wrote an article about it.

So, why does my motorcycle sound like bubbles? A motorcycle makes a bubbling sound because of a leak in the exhaust system, a faulty cooling system, or a malfunctioning fueling system, specifically from either the fuel injector or the carburetor. These issues are relatively easy to fix but should be addressed promptly.

So what does that mean and is it something bad? Should you immediately quit riding your motorcycle and get it repaired? Will the repairs be expensive? Are they difficult or could you do them yourself? We will dive into all of these questions below.

Why A Motorcycle Makes A Bubbling Sound

No matter who you are, no one wants to hear a strange sound coming from their motorcycle. It doesn’t matter whether it’s a banging sound, scraping sound, thumping sound, grinding sound, or bubbling sound. Repairs can be expensive on top of the inconvenience of having to work through the issues. This could mean not being able to ride your motorcycle for a while as well until the issue is resolved.

Depending on what is wrong, this could be a couple of dollar fix or a several thousand dollar repair. Fortunately, motorcycles are quite a bit cheaper to repair than cars, so the total cost (even for an engine replacement) is quite a bit less than it would be for a car.

As previously mentioned, a bubbling sound coming from your motorcycle could be a few different things. The hard part is determining where the sound is coming from. You can try to listen and follow the sound and that will hopefully tell you where the issue is, although sometimes it may be somewhat inconclusive. 

The first thing that could be causing this is an issue with your exhaust. This is most often a leak or crack somewhere in the exhaust system. Check your headers, muffler, and exhaust pipes for any leaks or cracks. These leaks can change the way that the air moves which can, in turn, make weird bubbling sounds.

The second thing that can cause this is your cooling system. Generally, a bubbling sound coming from your cooling system will be accompanied with engine overheating. If you notice these two symptoms, you will want to pull your motorcycle over immediately and shut it off or major engine damage can occur. If your motorcycle is not able to circulate coolant properly, the engine can begin to overheat causing the coolant to heat up significantly as well. This can result in a bubbling sound from your motorcycle.

Next, this could also be an issue with your motorcycle’s fuel system. Most often this could be a fuel injector that has become plugged up or even a carburetor that isn’t working like it should. Your engine relies on the consistent fuel supply in order to work properly. Any variation can result in incomplete combustion in the engine which can cause strange noises such as bubbling.

How To Fix A Motorcycle That Is Making Bubbling Sounds

Let’s say you have traced down the issue to your exhaust. What do you do? First, you need to figure out where exactly the leak is in your exhaust system. The easiest way I personally use to find exhaust leaks is by using a paper towel and slowly glide it along the exhaust system. Once the paper towel is over the exhaust leak, the forced air from this leak will push up against the paper towel, making it more obvious where that leak is. Please be mindful of your hands next to hot exhaust pipes; it’s a good idea to wear protective gloves while you do this.

You may also use a water and soap solution to locate the leak. In a spray bottle, mix together water and soap and spray it along the exhaust system (or in places where you suspect the leak may be coming from). Make sure the motorcycle is not on or that the pipes are not hot before spraying this solution as this can cause the mixture to evaporate quickly. Once the water-soap mixture has been sprayed, turn on your motorcycle; a motorcycle exhaust leak will manifest itself through bubbling from the solution you sprayed.

Once you have found the bad component, it is just a matter of replacing it. That is fairly easy to do with most exhaust components whether it be a pipe or a muffler.

Now, what if you traced the issue back to your cooling system? This one can be a little harder. Your cooling system is failing for some reason, and you need to figure out why. Oftentimes, your water pump will be the culprit. If it starts wearing out or stops working, then you will not have any circulation in your cooling system which can ultimately make a strange bubbling sound. The fix here is to replace the water pump.

Additionally, blockage in your cooling system can prevent the flow of coolant as well. If you recently replaced the water pump and know it’s not causing the bubbling problem, you can try flushing out your cooling system to get rid of those blocks..

Lastly, let’s discuss the fuel system being the culprit to your bubbling problem on your motorcycle. You’ll likely hear a bubbling sound if there is a blockage in the fuel system. If you have a fuel injector and it has become clogged, you will either need to use a fuel injector cleaner to clean it out or pull out the part and clean it with an ultrasonic cleaner.

More common, however, is having a clogged carburetor. Fuel injectors are much more efficient with fuel delivery, and it’s pretty common from carburetors to get clogged up. If your motorcycle has a carburetor and you hear a bubbling sound coming from it, you’ll likely need to give your carburetor a good clean by either using a good carb cleaner or simply removing it and using an ultrasonic cleaner to clean it out. See our other article here to learn how to clean a motorcycle carburetor without removing it.

Are Bubble Sounds An Indication Of A More Serious Problem?

So, are bubble sounds an indication of a bigger issue on your motorcycle? They definitely can be although they are usually not that big of a deal. For example, the bubbling sound could just be the result of a crack in your exhaust pipe. While you will probably want to get this fixed, it’s not going to cause any damage to you or your motorcycle if you ride around with it like that.

On the other hand, that bubbling sound could also indicate that your cooling system isn’t working at all, and that the engine is overheating. Ignoring this issue can result in your engine overheating and severe engine damage. This can ruin your engine or blow your head gasket.

Lastly, it could potentially become a serious problem if the bubbling is caused by a blockage in your fuel system. While this may not cause damage to your motorcycle, it may cause your motorcycle to simply die in the middle of a ride. Depending on where you’re riding, this could be dangerous to you as the rider; you don’t want your motorcycle dying in the middle of the freeway!

How Can I Prevent This Issue In The Future?

Is there anything that you can do to try to prevent this? This can come from a lot of different places so it’s hard to say 100%. There are things that you can do to take care of each system. In terms of your exhaust, you can regularly inspect your exhaust system to ensure there are no leaks. Some states will require emission tests that will let you know if there are any leaks.

In terms of your cooling system, regularly flushing and replacing coolant will help ensure it stays as healthy as possible and that any contaminants in the system get removed. Lastly, in regards to your fuel system, using a fuel additive and fuel filters to clean your injectors and fuel system is one great way to help it keep running great.

Kyle Cannon

Kyle currently works as a mechanical engineer and graduated with a minor in automotive engineering. He loves restoring motorcycles, has a vast knowledge of how they work, and has sold his restoration projects to customers from all over the United States.

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