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What Causes a Motorcycle To Backfire [Video Fix]

Are you tired of having the backfiring noise when you ride your motorcycle? Here’s what you need to know. Motorcycle backfire can be annoying because it produces such a loud popping noise.

Motorcycle backfire can be inherently bad because unburnt fuel is exploding in a mistimed manner; this results in lost power and lower mileage for the motorcycle.

There are several solutions for backfiring. However, let’s look at what a backfire means and why it happens.

What is Motorcycle Backfire?

An unwanted mixture of gas and air travelling through the exhaust pipes triggers a motorcycle backfire explosion. Unburnt fuel mixes with hot air from the combustion chamber to the exhaust system and releases into the open air. This means that the air-fuel mixture in your motorcycle’s combustion chamber is either too rich or too lean. Your motorcycle’s engine will make a loud backfire sound as a result.

When the wrong air-fuel mixture enters the combustion chamber, a portion of the fuel doesn’t combust. This unburnt fuel then expands suddenly at high temperature in a mistimed manner, which causes a backfire.

Backfires are bad for motorcycles.

When there is a backfire, most of the unburnt fuel ends up outside the bike, resulting in a loss of power and poor mileage.

If the engine is running on the wrong air-fuel ratio and does not have an oxygen sensor, the engine is prone to overheating. This happens when the exhaust pipe gets too hot because of the fuel burned within it. This causes the exhaust pipe to get bluish or change color.

The exhaust popping sound is another problem of motorcycle backfiring. It’s annoying, and if you live in a quiet neighborhood, prepare for some irate neighbors cursing you.

How to Prevent Motorcycle Backfire?

Backfires occur due to various reasons. Let’s talk about them one by one. 

1. Rich Air-Fuel Mixture

A rich air-fuel mixture is a high proportion of fuel to air. Fuel does not burn completely when a rich air-fuel mixture enters the engine from the carburetor.

The remaining unburned fuel will travel to the exhaust and detonate there when it encounters high-temperature air. Motorcycle exhaust backfiring is caused by detonation. The solution is to check if the air filter is clean or if the carburetor needs calibrating.

2. Lean Air-Fuel Mixture

The opposite of a rich air-fuel mixture is a lean air-fuel mixture. The amount of air in a lean air-fuel mixture is much more significant than the amount of fuel present. Fuel will be in excess in a rich air-fuel mixture, while air will be in excess in a lean air-fuel mixture.

A fast engine causes engine backfiring and uneven exhaust gas, which compresses the air inside the cylinder; this, in turn, harms engine performance.

Solution. When a lean air-fuel mixture is causing problems in your bike, it may be the carburetor or the inlet valve causing low fuel entry into the engine.

Before making any other changes, you must inspect both the carburetor and the inlet valve.

Once you have the problem fixed, you’ll never hear the sound of a motorcycle backfiring again.

3. Masked Spark Plugs

Masked spark plugs are essential to engine components to ignite the compressed air-fuel mixture in the combustion chamber. But they can get deposits on them.

If the spark plug has deposits formed, it will not produce a spark in the combustion chamber.

The best ignition system for a motorcycle can be a spark plug mask. When it’s applied correctly, it can prevent spark plug fouling in the first place.

If the problem is not solved, the best solution is to replace the spark plugs. Every time you service your motorcycle, you should inspect the spark plugs to ensure good condition.

You may have to replace the spark plug entirely if a masked spark plug causes the problem. Use a wire-type feeler gauge to see if there is a spark plug gap.

To determine if your spark plugs are at fault, you must find the correct spark plug gap. Typically, it should fall within the tolerances specified by the manufacturer.

4. High-flowing Exhaust

One of the reasons your motorcycle backfires is that it has a large exhaust pipe at the back and a short pipe. If your bike has a long pipe and a small opening at the back, it has a high flowing exhaust system.

The common phenomenon of motorcycle exhaust backfiring during deceleration (Decel Backfiring) occurs because of a short exhaust pipe and large opening. The greater the airflow through an exhaust system is, the more likely that exhaust backfiring may happen during deceleration.

A high flow exhaust system in your motorcycle can result in a high amount of deceleration backfiring. Solution: Don’t worry much if the backfiring is because of a high-flowing exhaust system.

There’ll be no problems caused by exhaust pipe backfiring. It may cause some noise, but that’s about it. You can replace the exhaust pipe with the larger one to stop backfiring. Again, this is not at all required.

5. Clogged Jets

Backfiring on your motorcycle can be caused by clogged jets. Fuel flow in the carburetor is inhibited by the accumulation of dirt in the jets, which results in a lean air-fuel mixture entering the combustion chamber.

So, getting dirt in the jets of the airbox of your motorcycle will result in backfiring. Dirt in the jets in any of the jets – pilot jet, main jet, or needle jet – will lead to backfiring in your motorcycle.

Clogged jets can be fixed with a simple procedure. These jets have accumulated much dirt over time. Clean the clogged jets by removing your carburetor as well.

6. Dirty Carburetor

Dirt in the carburetor will alter the mixture of air and fuel that enters the combustion chamber. An engine’s carburetor mixes air and fuel and then delivers the combination to the combustion chamber.

There is dirt in the carburetor, the fuel and air ratio is incorrect, and the fuel flow into the engine is disrupted. This results in either a rich or a lean air-fuel mixture.

The solution is to clean the carburetor once a year in both cases. Cleaning the dirt out of the carburetor will prevent backfiring. You can avoid any potential carburetor issues by following a yearly cleaning schedule.

Fixing a motorcycle backfire

When you know why your motorcycle has backfired and what can be done to avoid it in the future, then addressing the cause will fix the backfiring problem. The leading causes of backfiring in motorcycles include:

Tune the fuel pump: The pump must be tuned if the engine runs rough. Preventive maintenance will help, but the best time to adjust is when the motorcycle is cold because the fuel has already cooled down.

As you’re riding your bike, keep an eye out for carburator tuning: When it’s clogged or dirty, the air filter won’t allow the engine to draw in the proper amount of air, and the carburetor won’t perform as it should.

You will want to check the air filter for dirt, and if the filter is blackened or has too much dirt clogged, you will have to replace the entire air filter. Clean the jets and carburetor if the dirt in the jets and carburetor is causing the backfire.

The best time to clean the carburetor is once a year. You should also check the spark plugs and replace them if they’re damaged or have a poor spark. This will ensure better engine power and mileage.

Changing a spark plug is better if the gap is not within the acceptable range. The muffler must be replaced, and should also consider changing the exhaust pipe; this isn’t required.


Finally, the motorcycle backfire is a common problem that can cause loss of power and reduced mileage for a motorcycle. It’s important to note that a backfire can be dangerous since it can damage the engine.

Backfiring also leads to the engine and exhaust overheating. The noise generated from backfire can be annoying, especially if you live in a quiet neighborhood. The main reasons for motorcycle backfire include – rich or lean air-fuel mixture, masked spark plugs, high flowing exhaust, clogged jets or dirt in the carburetor.

There are a few things that can make a bike work poorly. The first thing to fix the problem is to adjust the carburetor. Next, you should check the air filter and inspect the spark plug. If that’s not enough to get the bike working well again, it’s time to replace it.

Your motorcycle is now ready to be ridden without any backfiring if you’ve addressed the problem.