Why Does My Dirt Bike Backfire?

Backfire happens due to the wrong mixing ratio of air-fuel that affects the emission system. Excess fuel or air can be the reason for your dirt bike backfire. The heat produced at the exhaust causes ignition of the fuel, which results in incomplete combustion.

Why does a Dirt Bike backfire? It is the most asked questions and frequently searches on the internet. Even many related queries are made, like does a dirt bike backfire when it is in idle condition? Is it on acceleration and deacceleration?

Many people are there in this world. You do not like the loud sound, especially when it is coming out from a dirt bike, and it is so irritating no one can stand.

You will also not feel good when your bike backfires; then, the sound will trouble others.

I am sure that you are searching for this. Why does my Dirt Bike backfire on the internet to get rid of this? It is a great intention not to go the other people for the sake of fun and enjoy the adventure. Taking steps to resolve the issue and keep the bike in good condition will help you.

Now we will discuss the common issues why backfires happen in a dirt bike. But before that, we will know what precisely a backfire is? If you don’t know at what condition you should change your clutch, we have described it here.

What is a Backfire?

Due to emission system malfunction in a dirt bike engine, a high level of the air-fuel mixture results in incomplete combustion. Thus heat of exhaust ignites the fuel. It is called a backfire.

Standard ignition happens inside the combustion chamber, and if there is no ignition, it means the engine will stop has an interruption.

The backfire explosion happens during the intake or exhaust both produce the loud sound which makes an irritating noise.

You can see a flame from the exhaust due to the partial compression. The rider can feel a jerk during the riding.

Suppose you are going for a ride on your lovely dirt bike, but a loud sound scares you. What was that? What kind of sound your bike is producing? These questions may arise in your mind; actually, we are talking about backfiring. This article is all about “Why Does My Dirt Bike Backfires?”. 

Before going deeply, you need to know what Backfiring is? If there is a high amount of air or fuel in the combustion chamber, this could lead to an explosion. But, if it doesn’t happen, then your dirt bike starts producing noise.

All over in a simple word, we can say that Backfiring means malfunctioning of the emission system due to the wrong ratio of the air-fuel mixture. Let’s see in detail what are the causes of backfires. 

Causes of Backfiring and Its Consequences:-

You came to know about Backfiring, and now it’s time to see its causes and harmful consequences. You may notice your bike start running either lean or rich. If your dirt bike is running lean, that means air is higher in ratio than the fuel. On the other hand, if it’s going rich, it means the mixture contains more fuel.

So, always fill your bike’s tank with a correct ratio; otherwise, your bike can explode. You can check this by yourself. Notice the carburettor and jets; you may find the causes of backfires; after that, don’t forget to clean them. 

You should know one more thing, like what happens if you ignore those noises and keep your bike the same. Let me tell you, such steps are entirely foolish.

Initially, a single backfire occurs that’s not so dangerous. But keep your eyes on them and fix them quickly. There are other kinds of backfires where you can’t find them easily, such as silent tsunamis.

Always notice the combustion sounds; if it’s louder than the usual days, take your dirt bike to the mechanics immediately. If you leave it, there are many cases where a bike catches fire which puts your life at high risk or the bike’s engine becomes useless. 

How to Prohibit Backfires?

I think you got enough knowledge about ” Why Does My Dirt Bike Backfires”. Do you know how to handle it without any mechanical help? Yeah, we are going to see the crucial steps which may reduce or prohibit backfires. 

  • Fuel Mixture & Its Quality- 

Dirt bikes already cost high as once you have invested such an enormous amount, why need to deal with the cheap fuels. Whenever you fill the tank, make a perfect mixture. And if you are purchasing fuel for your dirt bike, don’t compromise just for a few amounts; it can lead to damages. 

You should also be aware of cleaners, use high-quality cleaners to keep dirt and gunk away from the bike. And do it once a month, this step will help extend the lifeline of dirt bikes, and you might hear those annoying sounds anymore. 

  • Cleanliness of Air Filter- 

Air filters are the most fundamental part of a dirt bike. By keeping a clean air filter will extend the lifeline of your dirt bike. Air filters restrict the foreigners’ things to mix with air fuel and keep engines safe. While filtering the air, these filters collect dirt or mud on the other side, cleaning it all once in six months. Or if there is any damage, then it’s better to replace it with the new one. 

  • Take Care Of Carburetor Jets-

The carburettor helps mix the air-fuel mixture in a good ratio and then supply it to the combustion chamber. But, if something is clogged in it, it can cause backfires.

First, remove the carburettor and then separate its bottom part known as float. Later on, you will see a jet inside it; remove it carefully.

Now the last step is to open up the outer parts with the help of a screwdriver. Once you have done the separating process, clean it one by one and reinstall it in the opposite removal process. Keep cleaning Carburetor jets once a month. 

If you do these three processes punctually, your bike will never face backfires. Here we are done with the common problem related to ” Why Does My Dirt Bike Backfires”. And now we have other issues too that backfires in different situations. 

Suppose you want to know the answer to this question before that tell me one thing. Do you notice the speed of your dirt bike? If your bike is running lean, then it causes a backfire during deceleration. When the engine fires, due to unbalanced mixing of air-fuel, unburnt gases or fuels produce fires in the exhausting pipe and result in backfires. 

What are the different conditions for backfire?

If you have a dirt bike and an emission system malfunction, just like a leak in exhaust running leech or running Lean backfire occurs.

If the engine is running rich, then the consumption of fuel will be more than the air. And if the engine is running lean, then combustion of air will be more than the fuel.

In both cases, the result is incomplete combustion due to the improper ratio of the air-fuel mixture. In this situation, the fuel is ignited by the heat produced by the exhaust, which causes loud and irritating noise.

Stock muffler, which is assembled in the bike, is designed to ensure the complete and proper function of the engine. If there is a difference in pipe design and other specifications, it can result in increased airflow to the bike, which causes the bike fire in the exhaust.

Also, many different causes of backfire like weak fuel pumps, clogged fuel filters, and low feel pressure all of these three of these issues directly affect the air-fuel ratio.

Why Does My Dirt Bike Backfire On Deceleration?

Backfires are a result of unburnt fuel clogged in the exhausting pipe. A high flow of fresh air increases the temperature of the exhaust pipe and can destroy those garbages and produce sounds as something explodes into the pipe.  

Dirt Bike Backfiring On Acceleration:-

There are a lot of reasons that produce Backfiring on acceleration. The first and the most common cause is the lousy ratio of air-fuel mixture that forces the ignition process to occur in the intake or exhaust. It also happens when there is a leakage in the exhausting system or wrong catalytic converters present. 

When the dirt bike starts Backfiring on acceleration, its causes are low compression, leaks in the fuel tank, or air filters—broken valve or damaged carburettor. Check these parts one by one, and you will get the leading cause of Backfiring. 

Dirt Bike Backfire When Kickstart:-

While starting your dirt bike and it starts Backfiring instead of running, what causes it to do so. Whenever you start your dirt bike for the first time on that day, fuel mixtures take time to reach the combustion chamber where these fuels burn and generate fires to start the dirt bike.

When you put on the valve, the air-fuel mixture slips towards the chamber to complete the whole process from burning to firing. Still, if insufficient time is given to the process, very few fuels start burning in the chamber, and low fuel or mixture is one reason behind backfires. To prevent backfires while kickstart, wait for 10-15 mins after putting the valve on; this much time is enough for the combustion. 

Dirt Bike Backfires When Trying To Kickstart:-

This problem is similar to the above issue. But the only difference is you are trying to kickstart. You must know that start your dirt bike with kickstart; you need to wait for a perfect time to kick it.

It might be possible that you have forgotten to fill the air-fuel mixture or forgot to put it on the valve. In both cases, dirt bike backfires.

You must want to know why this happens; when less mixture is present, one of the parts of the mixture reaches the exhausting pipe and produces pop sounds means backfires.

On the other hand, is the valve, it allows fuel to flow into the chamber, maybe you didn’t notice it. So, the previous burnt fuel coming out from the pipes backfires. Before trying to kickstart, check these two systems. 

Dirt Bike Backfire Through Carb:-

We have discussed already that a lean running bike means a sign of backfires. When extremely lean carburettor mixtures are present in the bike, it causes backfiring. When this lean mixture flows, it burns slowly in the combustion chamber or can remain unburnt. This unburnt fuel is present inside the chamber until the next stroke is given to it, fresh fuel joins the chamber, and the previous one pushes out via exhausting pipes.

Here is the case of malfunctioning through carbs; replace this carb, or this could burn your whole bike. If it doesn’t work, carburettor monitoring the mixture ratio means backfires are not so far away. 

To prevent such backfires through the carb, remove the carburettor and then separate the float. The next step is to remove jets and then put out outer parts to clean them with the help of cleaner spray. 

Dirt Bike Backfires When Slowing Down:- 

When you slow down your dirt bike and hear a noise coming out from the exhausting pipe, the bike backfires at that moment; when you slow down the dirt bike, more fresh air starts entering the exhausting system. If there are unburned fuels present, air and unburnt fuel react and become explosive material.

More air makes the explosion higher. The most common reason for backfires is also responsible for this problem. Fresh fuel mixture occurs in the engine and old one threw out into the exhaust pipe where usually backfires happen. 

I’m suggesting you make sure your carburettor is working or not to supply a sufficient ratio of the mixture. Otherwise, such explosions keep disturbing you and damaging bike engines. 

Note:- In a simple sentence, if you keep cleaning your dirt bike regularly, backfires will never fall on. As your body needs daily cleaning to prevent health issues, your dirt bike needs the same to avoid backfires. 

Is it bad for a dirt bike to backfire?

Backfiring is not a good thing it is harmful for engine. Running lean or rich is going to heat your engine more. If engine runs in such condition exhaust will damage too.

Why does my dirt bike backfire on deceleration?

When you deaccelerate and there is excess oil in combustion chamber then it caues backfire on deacceleration. Backfire need more fuel to be burnt so it reduces the efficiency.

Can a backfire damage an engine?

Whenever you see the backfire in your bike then you should pay attention to it as it can damage your engine and even it can cause power loss, reduced fuel efficiency and performance.

Is backfiring lean or rich?

Backfiring can occur in both condition either when engine running lean or rich.


Many riders frequently ask this question, “Why is my dirt bike backfiring”.

So in this article I have explained why does a dirt bike backfire. I have also explained the different condition when backfire happens.

Here I have also discussed the causes of the backfire, and we have also given you the steps to resolve this on time. .

If you like the post and see it as this helpful, please subscribe to our newsletter.

Thomas A. Talley

I’m Thomas. Since childhood, I am fond of bikes and hence dirt bikes are my passion now. Ever since then, I’ve been giving advice to the beginners and this has become my hobby.

Recent Posts