Dirt Bike Backfires: 7 Causes And Fixes (Explained)

It’s irritating when your dirt bike backfires. Don’t worry, I’ve also had this issue many times, but the good news is that I have good experience with it and have compiled the 7 likely causes. If you don’t want to be in this scenario again, read the article to learn the causes and the remedy.

An improper air-fuel mixture will cause your dirt bike to backfire. Incomplete combustion occurs when air and fuel aren’t mixed properly. It’s why dirt bikes backfire. Dirt bike backfires when you accelerate, decelerate, or start it.

Now we’ll discuss dirt bike backfires. But first, we’ll define “backfire.” If you don’t know when to update your clutch, read this.

What is called a “Backfire”?

Incomplete combustion occurs when a dirt bike’s emission system malfunctions, causing a high air-to-fuel combination. Exhaust heat ignites gasoline. Backfire.

Standard ignition occurs in the combustion chamber; without it, the engine stops.

When the backfire explosion happens during intake or exhaust, it makes a loud, annoying sound.

Due to the exhaust’s partial compression, there is a visible flame. During the trip, the rider can feel a jolt.

Suppose you are going for a ride on your beautiful dirt bike, but you are frightened by a loud noise. What did you say?

What type of sound does your dirt bike make? You might be asking yourself these questions; we’re discussing backfiring.

Backfiring is the malfunction of the emission system caused by an improper air-fuel ratio. Let’s examine the root reasons of backfires in depth.

7 Causes Why A Dirt Bike Backfires?

For understanding the reason of your dirt bike backfire you need to read this section very carefully. It can help you identify and solve this issue.

Here are the 6 causes of dirt bike backfire:

1. Clogged Carburetor

A clogged carburetor is one of the most prevalent causes of a backfire on a dirt bike. Inside the combustion chamber, it helps to mix the air and fuel together. After combustion, the engine is then pushed by the power stroke.

On the other hand, when dirt or a choked passage of fuel prevents combustion from taking place at the appropriate time. It slows down the jet, and because of this, the acceleration also slows down.

To understand proper cleaning method of a carburator you should read another article which I have written for you. Click here and read how to clean a dirt bike carburator.

2. Dirty Carb Jets

The backfire that might occur in the engine of a dirt bike is also caused by dirt jets. When the accelerator is pressed, the jets in the car respond by giving the pistons additional power, which causes the dirt bike’s speed to increase.

If the carb jets in the dirt bike are dirty, the fuel injection will not be proper, which will cause the engine to backfire.

3. Improper Ratio of Air and Fuel

If you believe that the aforementioned causes are to blame for this issue, then please allow me to add more possibility to the list: the improper ratio of air to fuel. If your dirt bike is running rich, this means that the mixture has excessive amounts of fuel and insufficient amounts of air.

On the other hand, if your bike is running lean, this means that the combination contains excessive amounts of air and insufficient amounts of fuel.

If the air-fuel ratio on your dirt bike is too high, the engine may backfire as a result of the excess richness.

In this particular situation, because there is an excessive quantity of fuel, the combustion does not end in the chamber, and the additional fuel makes its way to the exhaust system through the exhaust valves.

As a consequence of this, burning of the fuel will take place during the process of exhausting, which will result in backfire.

4. Clogged Air Filter

In a dirt bike engine, the ratio of air to fuel must be a certain way for combustion to work right.

Because the air filter is clogged, not enough air is allowed to reach the combustion chamber. This makes the engine run too rich, which in turn causes the exhaust to backfire.

5. Damaged Spark Plugs

An incomplete combustion might result from spark plugs that have been damaged. This might result in a misfire ignition.

Ignition will also take place in the exhaust system, and any unburned fuel that is left over will burn, which will cause the engine to backfire.

A mistimed ignition during compression may also be caused by a faulty spark plug.

6. Low Compression

When the air and fuel combination enter the combustion chamber, compression takes place. If the compression is too low, the spark plug won’t be able to ignite the air and fuel mixture.

If there is a leak in the exhaust valve, then it is possible that this will also produce low compression. For more detailed information, you can read our other article, Why Does a Dirt Bike Have Low Compression, by clicking here.

7. Low Fuel Quality

Since dirt bikes are designed to perform well on the tracks, the usage of fuel of a high quality is required. You may check the octane requirements of your dirt bike in the manual for your dirt bike. Low-grade fuel does not have the required amount of octane.

The engine will suffer damage if you use fuel of a lower quality, and the fuel tank will become contaminated with dirt and debris. The exhaust system will also be impacted when dirty gas passes through it.

When Does A Dirt bike Backfire?

1. Backfire on Deceleration?

The accumulation of unburned fuel in the exhaust pipe might cause a backfire to occur.

It is possible for those garbage to be destroyed and for sounds to be produced as something explodes into the exhaust pipe if there is a strong flow of fresh air and the temperature of the exhaust pipe is increased.

2. Dirt Bike Backfiring On Acceleration

The occurrence of backfiring during acceleration can be caused by a variety of factors.

The poor ratio of air to fuel in the mixture is the primary cause, since it causes the ignition process to take place either in the intake or the exhaust. This is the most common cause.

It can also occur if there is a leak in the exhaust system or if the improper catalytic converters are installed.

Low compression, leaks in the fuel tank or air filters, cracked valves, or a damaged carburetor are the most common causes of backfiring in a dirt bike during acceleration.

Check each of these parts on its own, and you’ll find the main cause of the car backfiring.

3. Dirt Bike Backfire When Kick Started

If, when you try to start your dirt bike, it begins backfiring instead of running, what could be the source of this behavior?

If you were to start your dirt bike for the first time that day, it would take some time for the fuel mixtures to reach the combustion chamber, which is the part of the engine where the fuels are supposed to burn and generate fire in order to get the dirt bike going.

As soon as you turn the valve, the air and fuel combination begins to go toward the chamber, which allows everything to be finished, from burning to fire.

However, if the process is given inadequate time, a very little amount of fuel will start burning in the chamber. And a low amount of fuel or mixture is one of the reasons why backfires occur.

After turning the valve on, you should wait 10 to 15 minutes before trying to kickstart the engine. This is enough time for the combustion process to take place.

4. Dirt Bike Backfires When Trying To Kickstart

This issue is comparable to the one that was discussed earlier. The one and only distinction is that you are attempting to kickstart.

You have to be aware that in order to get your dirt bike going, you have to use the kickstart, and you have to know exactly when to kick it.

It is likely that you forgot to put the air-fuel mixture on the valve or that you forgot to fill the tank with the air-fuel combination. In all scenarios, the dirt bike has a misfire.

You must be curious as to why this occurs; when there is less mixture present, one of the components of the mixture reaches the exhausting pipe and creates pop sounds, which indicates that it backfires.

On the other hand, the valve enables fuel to flow into the chamber; perhaps you were unaware that this was happening.

Therefore, the previously burned fuel that is expelled from the pipes causes a backfire.

Check these two systems before attempting to get the engine started.

5. Dirt Bike Backfires When Slowing Down 

If you are decelerating on your dirt bike and hear a noise coming from the exhaust pipe, this indicates that the bike is backfiring at that precise instant. When you decelerate on a dirt bike, more fresh air is drawn into the exhaust system.

In situations when there is fuel that has not been burned, the combination of air and unburned fuel can combine to produce a substance that is explosive.

The explosion will reach greater heights if there is more air. This issue may be traced back to the most prevalent cause of chain reactions, which is also the source of the problem.

In the engine, a new fuel mixture is created, and the previous one is sent out into the exhaust pipe, which is typically where backfires take place.

I think you should check how your carburetor works to see if it is giving you the right amount of the mixture. Otherwise, such blasts will continue to annoy you and damage bike engines.

Note: In a summary, you may prevent backfires from occurring on your dirt bike by maintaining a consistent cleaning routine.

Similar to how you should clean your body on a daily basis to avoid developing health problems, you should clean your dirt bike in the same manner to stop it misfiring.

Consequences of Dirt Bike Backfiring:

You are now familiar with the concept of backfiring; the next step is to examine its root causes and the damage they might do.

You might discover that your bike is suddenly running either too lean or too rich. When your dirt bike is operating in a lean condition, the ratio of air to fuel will be higher.

On the other hand, if it is getting rich, this indicates that there is a greater proportion of fuel in the mixture.

Therefore, make sure that you always use the appropriate ratio while filling the tank of your dirt bike. Failing to do so could result in the dirt bike exploding.

You are able to verify this on your own. Pay attention to the carburetor and the jets; you might discover the reasons for the backfires; after that, don’t forget to clean them up.

You need to be aware of one more thing, such as what occurs if you choose to disregard such noises and maintain the same settings for your bike.
Permit me to inform you, taking such actions is completely illogical.

At first, there is just one backfire that does not pose a significant threat. However, keep a close check on them and make the necessary repairs as soon as possible. Backfires come in a variety of forms, some of which are more difficult to locate than others, such as silent tsunamis.

Always keep an ear out for the sounds of combustion; if they are stronger than usual, you should take your dirt bike to the mechanic as soon as possible.

If you leave it alone, there is a good chance that the dirt bike will catch fire, putting your life in grave danger, or that the engine will stop working, rendering the dirt bike useless.

How to Fix Dirt Bike Backfire?

I think you have enough facts to identify why a dirt bike backfires. Do you know how to do it yourself? Yes, we’ll see the key steps that can prevent backfires.

1. Maintain Air-Fuel Mixture And Its Quality

The price of dirt bikes is already expensive. Why do you have to deal with cheap fuel after making such a large investment?

Always mix the fuel perfectly before adding it to the tank. Don’t cut corners while buying fuel for your dirt bike because doing so could result in damage.

Consider using high-quality cleansers to prevent dirt and other debris from getting on the bike. And repeat it every month. You might stop hearing those inconvenient noises after taking this step, which will help extend the life of dirt motorcycles.

2. Cleanliness of Air Filter

The most essential component of a dirt bike is the air filter. Your dirt bike’s lifespan will be increased if you maintain a clean air filter.

Air filters keep engines safe by preventing extraneous objects from contaminating the fuel.

These filters absorb dirt or mud on the opposite side while filtering the air, and they are cleaned completely once every six months. It is also preferable to buy a new one if there is any damage.

3. Take Care of Carburetor Jets

The air-fuel combination is mixed well by the carburetor, which then provides the combustion chamber with it. But if something is stuck in it, it may have unintended consequences.
Start by removing the carburetor and separating the float from the bottom of the device. You’ll later see a jet within; cautiously remove it.

The final step is to use a screwdriver to pry open the outside components.

Once the separation process is complete, clean each component individually and reinstall it using the reverse removal procedure. Maintain your monthly carburetor jet cleaning schedule.

Your bike will never have a backfire if you perform these three procedures on time. We have now addressed the typical issue with dirt bike backfiring. We also have current problems that can backfire in many circumstances.

Let’s say that before telling me something, you want to know the answer to this question. Do you notice how fast your dirt bike is going?

When you slow down, a backfire occurs if your bike is running lean. When the engine starts up because the air and fuel mixture isn’t right, unburned gases or fuel catch fire. This causes backfires and fires in the exhaust pipe.

4. Check Spark Plugs

Damaged spark plugs can lead to backfire by causing ignition to misfire. In such a state, you can inspect your spark plug.

About testing the Spark plugin, I’ve created a whole separate article. You can read how to check a spark plugin by clicking here.

Frequently Asked Questions [FAQ]

Is it bad for a dirt bike to backfire?

Backfiring is not a desirable situation. It harm the engine.

Your engine will heat up more if you run lean or rich. In such a situation, running the engine will also damage the exhaust.

Can a backfire damage an engine?

If there is too much oil in the combustion chamber as you decelerate, it backfires. Backfire decreases efficiency since it requires more fuel to burn.

Is backfiring lean or rich?

Backfiring may be the result when the engine’s mixture is too rich.


I’m hoping this information will l assist you identify the real cause of your dirt bike’s backfiring so you can attempt to resolve it.

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