Motorcycle Backfire

Why Does My Motorcycle Backfire and What Causes Backfiring?

Do you own a motorcycle? Or you ride one even if it is not yours. Then, you should know that it is important that you take good care of the motorcycle to keep it running fine. 

There are checks to be done periodically and some daily. These checks are crucial to ensure the smooth running of your bike. You do not want your bike to stop working abruptly along the road and leave you stranded.

So, there are certain things to watch out for to be sure your bike is running smoothly. One of this is the sound of your motorbike. Your motorcycle tends to make a growling sound which indicates that the engine is still in perfect condition. 

This growling sound gives the riders a satisfaction feeling because nothing beats a motorbike engine that works perfectly. 

But what happens when your motorcycle backfires? Find out more about this in this article. Learn about the causes and possible solutions.

It is quite common for a motorcycle to backfire so you should anticipate this every time you ride your two-wheeler. Motorcycle backfire usually happen in the exhaust or intake of the bike. 

It might scare you the first time it happens but you do not have to fret. It usually happen because uncombusted gas or fuel is in the exhaust pipe. 

Causes and Solutions of Motorcycle Backfire

Below are prevalent causes of motorcycle backfire:

Wrong Exhaust Upgrades

Some motorcycle owners and riders love to fix an additional aftermarket exhaust to their motorcycle. Although it helps them to save money, but it is considered a wrong move because it causes motorbikes to backfire

The reason is simple, aftermarket exhausts are not designed for some certain bike, rather their primary function is to enhance the bike’s performance. It does not often work fine with standard jetting. 

The solution to this issue is for riders to ensure their motorcycle jets properly. Alternatively, riders can ensure that their motorcycle is tuned correctly to suit the recent aftermarket exhaust

If you practice this solution well, you do not have to worry about your motorcycle backfiring because of wrong exhaust upgrade.

Clogged Jets

Your motorcycle’s carburetor has 4 primary components that enables the rider enjoy smooth ride when he turns the throttle. But dirt can clog up in the carburetor and prevent it from working well. 

The four primary components include:

  • Needle Jet: this is needed for the jet to take down and up when the rider turns the throttle between fifteen and sixty percent. 
  • Jet Needle: this controls the quantity of fuel flow when the rider opens and closes the throttle between twenty and eighty percent power. 
  • Main Jet: it controls the fuel quantity when the rider turns the throttle between fifty and hundred percent power. 
  • Pilot Jet: it controls the fuel when the motorbike engine is idle.

A carburetor cleaner is required to unclogged the jet and remove the dirt. The cleaner comes with a straw attachment and a spray can. When using this cleaner, you have to wash all the components in the carburetor to aloe furl to flow easily through the jets. 

Failure to clean these 4 components properly will lead to motorcycle backfire. 

Faulty Carburetor

You have to take good care of your bike. One of the ways to do this is by checking the carburetor frequently especially when your motorbike backfires. 

You must have an understanding of how the carburetor works. Fuel has difficulty flowing through a dirty or faulty carburetor which might make your engine to run leanly. Consequently, this will cause your motorcycle to backfire and fail to accelerate. 

However, you can proffer solution to this issue by cleaning the carburetor to allow easy flow of fuel. You can use a carburetor cleaner to remove all the debris and create a clear passage for fuel. 

Poor Timing

Motorcycle type vary and each has its type of timing. The 2 primary timing are points setup otherwise called condenser and the electronic timing. The electronic timing is the most effective timing of the two as regards time-saving and efficiency. 

Electronic timing was introduced a few decades ago and it has since made it effortless to troubleshoot backfiring problems because there are no much parts where you have to check for fault. 

The electronic timing employs a simplified working standard. It signals the ignition coil when the cylinder is in a compression stroke at the same time when the cylinder is ready to fire. The whole process is quite complex but the major thing is the timing. 

If you get the timing wrong, it affects the whole engine. Thus, if your electronically controlled motorcycle has a timing issue, there will likely be a mechanical timing issue as well. 

This will cause your motorcycle to backfire when you want to start the ride or even when you are riding. This also happens if your bike uses a condenser and points in its timing. 

One can manage this timing issue by manually setting a point using the instructions written by the motorcycle manufacturer or the information in the repair manual. However, this largely depends on your bike’s model because motorbikes have different mode of operation and designs. 

Excess Fuel

A substantial quantity of fuel is needed for the combustion to take place inside the cylinder. A lesser or excess quantity of what is required may cause the engines to develop problems.

Note that the fuel must mix with air in specific proportions for combustion to be successful. Excess fuel or air can disrupt the combustion process and cause severe damage to your bike’s engine. 

You may have heard people say that their bikes are running rich, which implies that the cylinders of their motorbikes are getting more fuel than air. This causes a rich condition to your bike when it happens and affects the performance of the engine. 

The result is a drastic reduction in your mile per gallon and cause your motorcycle to slow down. In worse conditions, your motorbike can backfire within the exhaust pipe. 

When there is too much fuel in the cylinder, it tends to impede the ignition process because the ignition will fail to burn down the fuel successfully during combustion. 

You can remove the excess fuel for the cylinder head using the exhaust valve. Once the fuel mixes with fresh air and the hot exhauster header, it combusts and creates a loud pop sound or a bang. This sound is usually scary and dangerous if it occurs while the rider is riding the motorbike. 

The good news is that this can be prevented by making sure that there is sufficient fuel in the cylinder to allow an easy combustion process. If you have not used your motorbike for a long time, disassemble the carburetor and clean it thoroughly before use. 

Once you have cleaned all the sections and components of the carburetor, be rest assures of smooth and better engine operation because fuel will flow easily.

Low-Fuel Grade

High quality fuel is what your motorcycle needs to run properly. So you must avoid low or substandard fuel if you want your motorbike engine to run well and last long. 

It is better to buy high quality fuel that guarantees smooth running of your motorbike’s engine than to buy low grade fuel at reduced cost and later face engine issues. It has been discovered that poor quality fuel causes your fuel tank to be filled with dirty gas. 

This contaminated gas can cause severe problems to your bike even while you are riding. It has a negative impact on your bike’s fuel injection and causes your motorbike to backfire once you hold the throttle to accelerate. 

The solution to this problem is straightforward. Ensure that you use only top grade and high quality fuel in your motorbike. Make it a standard and never go below that standard. 

High-grade fuel will provide your bike with cleaner gas and a clear fuel line. 

Shorter Exhaust Pipes

Short exhaust pipes usually tend to be challenging. To curtail this challenge, most states came up with laws on the length of motorcycles exhaust pipes. The laws are meant to prevent motorcycle backfire. The law stipulates the minimum length of an exhaust pipe such that it will not be troublesome for the user. 

Short pipes are often called shorty and are usually 12 inches or less. They function primarily to minimize loud exhaust sounds and give the motorbike a clean appearance. 

Short exhaust pipes give your bike gives your bikes an attractive look because of its small layout but it is not advisable to use anyone that is 12 inches short because it can cause exhaust to backfire. 

Because of their shortness, the exhaust pipes do not have an inbuilt baffle which reduces loud bags. The baffle is a little part of the exhaust pipe that performs a similar function like muffler does in cars. The baffle converts the raging flow of used up exhaust into a more quiet and manageable flow. 

Furthermore, shorty pipes backfire more often because they lack adequate pipe length needed to improve smooth air flow. 

There is a particular length of exhaust on different motorcycle models which promotes fuel efficiency and improves motorcycle’s overall performance. However, this involves a high risk of frequent backfiring. 

It is recommended that you go for motorbikes with longer exhaust pipes.


By now, you know why your motorcycle backfires. The major cause is the carburetor along with others mentioned above. 

Find solutions to these issues and enjoy a smooth ride.