Why Does My Motorcycle Backfire?

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Most motorcycles are set up to require them to have a correct ratio of fuel and air, which allows them to run fast and efficiently.

Motorcycle backfire is a phenomenon that occurs when the engine of your motorcycle gets too much fuel or air.

This problem directly causes a loss of fuel which reduces your mileage and eventually leads to the engine and the exhaust overheating.

The issue itself may not seem that harmful. However, it can cause you many other problems as time goes on.

If you have been pondering the question, “why does my motorcycle backfire?” then look no further as in this article, I will be explaining the question in its entirety along with the various fixes for it and other helpful tips you can follow to avoid it.

Here are some common causes for it:

  1. Faulty Carburetor
  2. Clogged Jets
  3. Shorter Exhaust Pipes
  4. Poor Timing
  5. Excess Fuel
  6. Low-Fuel Grade
  7. Wrong Exhaust Upgrades
  8. Faulty Spark Plug
  9. Dirty Fuel Filter

Before I get into the root causes of the problem, let me give a brief overview of the problem itself along with things you should know about it.

What Is Motorcycle Backfiring And What You Should Know About It?

Let's find out what motorcycle backfire is and how to avoid having this issue

As mentioned above, motorcycle backfiring is caused by a bad fuel/air ratio and results in a small detonation of unburnt fuel due to combustion happening outside the combustion chamber.

While I will be going over the causes and fixes later in the article, you should first understand the different types of motorcycle backfires that can occur when driving your motorcycle.

You must also know the significance of the air to fuel ratio inside your motorcycle and the consequences of motorcycle backfire, and why you want to avoid them.

Types Of Backfires

Multiple types of backfires occur at different points when driving your motorcycle. If you notice your motorcycle backfiring when rolling onto the throttle, it indicates a serious lean condition that is very harmful to your motorcycle’s engine.

The same results when your motorcycle is backfiring when fixed or steady on throttle. If your motorcycle backfires when rolling off the throttle, it does not cause any harm to your engine as it is just a release of combustible gases.

Make sure to understand these three types to see if you have a genuine problem or not.

Running Rich Vs. Running Lean

Running Rich and running lean are ways you describe the ratio of fuel and air inside your combustion chamber, where running rich means you have too much fuel, and running lean means too much air.

Both of these are conditions you should not face, as when you run rich, the lack of air causes a lack of explosion in the combustion chamber, which leads to excess fuel being passed out the exhaust, which results in a backfire.

Similarly, running lean leaves excess air and fuel that isn’t used up to cause yet another backfire.

Consequences Of Motorcycle Backfire

I briefly touched on this above and will expand on it here. A motorcycle backfire is, by all means, a fuel malfunction and must be fixed immediately. The combustion of fuel outside the engine always results in a loss of power.

This loss of power also translates to fuel efficiency as fuel is being wasted outside the combustion chamber. This results in lower mileage, and less distance traveled.

This issue also increases the temperatures of the engine, which, if it happens too much, can result in lower performance and engine failure.

What Makes A Motorcycle Backfire And How To Fix It

There are various reasons as to why your motorcycle can backfire. Mostly, this occurs due to uncombusted fuel or gas inside the exhaust pipe, but other times it could be the result of faulty components, poor timing, bad maintenance, low-quality fuel, and bad upgrades.

While some of these issues will happen on their own, some are the direct result of poor maintenance and care taken from the owner’s side, meaning depending on the person, the issue could happen more often.

Luckily, none of these issues are permanent, and most of them can be fixed by repairs or by changing the affected parts. Understanding the problems and how to fix them should easily prepare you to identify them when they occur and resolve them without constantly searching for solutions online.

I will now explain these problems in greater detail and tell you how to fix them.

1. Faulty Carburetor

If you frequently take your motorcycle out for a ride, you must make it a habit to check on your carburetor from time to time, and it should be one of the first things you check when you see your motorcycle backfiring constantly.

A good carburetor must allow the fuel to flow through it smoothly. If your carburetor is faulty or dirty, this cannot happen, and as a result, you start to run on lean, which prevents your motorcycle from accelerating and causes backfires. An easy fix for this is checking your carburetor and seeing if it could use a good cleaning.

Make sure that it is functioning properly and that it is properly cleaned. A good way to clean it is to use a carburetor cleaner.

If for some reason, it continues to cause backfires, then it must be a fault in the carburetor itself, in which case you will need to have it replaced.

2. Clogged Jets

This issue is closely related to the one above. Your motorcycle carburetor consists of 4 different jets. The pilot jet, the main jet, the jet needle, and the Needle jet.

These four components have their function and allow you to ride the motorcycle when the throttle is turned. Eventually, these jets can become clogged.

The more you ride, the more clog they accumulate over time, and eventually, it reaches a point where they get so clogged that they cannot work properly.

This results in your motorcycle backfiring. Yet another simple fix, you can use the same carburetor cleaner to clean these jets.

Make sure that they are fully open to ensure a smooth fuel flow. While this normally isn’t required by any means, you can also consider changing the jets or changing the carburetor entirely to avoid any headaches. Just make sure to keep the new one clean.

3. Shorter Exhaust Pipes

Short exhaust pipes have amassed a reputation for being quite troublesome, which is why many states here in the United States have rules and regulations regarding them. These laws exist solely to prevent motorcycle backfiring.

Despite being aesthetically appealing and minimizing loud sounds from the motorcycle’s exhaust, they simply do not have the length to enhance and ensure a smooth flow of air which results in a backfire.

The reason why exhaust pipes are a certain length, to begin with, is to promote fuel efficiency and motorcycle performance.

However, short exhaust pipes throw this efficiency away for aesthetic and cause major problems to the engine and fuel system of the motorcycle.

An easy fix is to simply purchase and use a longer exhaust pipe and avoid shorter ones. This will neutralize the problem and increase the performance of your motorcycle as well.

4. Poor Timing

Engine timing is integral to the functioning of the motorcycle as if the timing is off, then there will be quite a few problems with the engine. However, since the addition of electronic timing, issues like these have reduced significantly.

Each motorcycle has its timing, and in today’s era, this timing relies on the electronic timer and the condenser. While the electronic timer is quite helpful, this does not mean the problem has been erased as if, for some reason, the timing is off. It likely that a mechanical timing problem also exists.

This will cause your motorcycle to start backfiring while riding it or startup. While this problem sounds a bit complex, it is relatively quick to fix as you can easily correct the wrong timing by referring to a manual or manually setting a point. If you feel as if you are not confident in it doing it yourself, then I recommend a trip to a mechanic.

5. Excess Fuel

The entire issue regarding motorcycle backfiring revolves around the fuel system, which is why you must keep your fuel system working perfectly and supply it with a good amount of fuel.

However, this must be in the regulated amount as any more or less fuel in the system can cause backfiring and engine problems.

You must have a perfect balance between the air and the fuel as too much of either one can prevent proper combustion, cause improper combustion and lead to major engine damage.

You can easily prevent this from happening by making sure that there is a substantial amount of fuel inside the cylinders for combustion to occur and that the air to fuel ratio is also kept in check. Running rich and running lean, as explained above, are things which you should avoid.

6. Low-Fuel Grade

While it is essential to keep your motorcycle filled with enough fuel to manage, you must also make sure that the fuel you provide it with is high quality.

Poor quality fuel should be avoided as it can easily release dirty and contaminated gas, which has a lot of adverse effects when riding a motorcycle.

It directly impacts the fuel injection of the motorcycle and causes backfires to occur more frequently, so if you were purchasing low-quality fuel to save money, you should reconsider as it can cause you a lot of cash in the long run.

This problem can be avoided entirely if you make sure to purchase good or top-quality fuel and avoid the alternative as it leads to a much clear fuel line and gas tank.

That being said, you should do your best to avoid low-quality fuel so that you can get better performance and mileage from your motorcycle.

7. Wrong Exhaust Upgrades

While upgrading your motorcycle is usually done to enhance its features, some upgrades usually come with a tradeoff or are just downgrades in disguise. Purchasing aftermarket exhausts may save you money.

However, they are a huge cause of backfires in motorcycles. Many of these exhausts are designed for specific motorcycles and are not compatible with other motorcycles, which is why you get a new or different exhaust. It causes a decrease in performance and increases the chance of backfires occurring.

To fix this issue:

  • You must make sure that your motorcycle is compatible with your motorcycle.
  • Another way you can prevent this from happening is to have your motorcycle tuned correctly to suit the exhaust.
  • Doing all of this will significantly lower your chances of the exhaust upgrade, causing backfires and other performance issues.

8. Faulty Spark Plug

The spark plug is an integral component in the ignition system of your motorcycle and sends voltage from its base to create a spark that ignites the air and fuel mixture in the combustion chamber, which results in the engine starting.

While it may not inherently look as such, the spark plug can cause many issues, especially motorcycle backfiring, if it has a fault or if it is defective.

This results from bad ignition timing, which results from the faulty component, which results in the motorcycle backfiring.

Before you go and start replacing the sparkplug, which is the most direct and fastest way to resolve the issue, you should make sure that the spark plug is causing the issue.

Once you confirm that the spark plug is to blame, then simply order a new one and replace the old one.

9. Dirty Fuel Filter

The bike’s fuel filter is another essential component of the fuel system that prevents dirt and debris from entering the fuel system, saving you from various running and starting issues. It also prevents these foreign particles from changing the flow and pattern of the injectors.

Eventually, depending on how much you drive your bike, your fuel filter may accumulate dirty and begin to struggle, which leads to your motorcycle backfiring.

This problem can be avoided entirely by ensuring the fuel filter the attention and maintenance it deserves by making sure it is cleaned now and then.

The cleaner the fuel filter, the smoother the flow of oil in the system, so make sure to clean it regularly. If you believe it is damaged, you can quite easily get a replacement for it.

Tips To Avoid And Prevent Motorcycle Backfire

Here are a few tips and recommendations you should follow to avoid these problems from occurring:

1. Regular Cleaning

Quite a few of the problems I mentioned above are the direct result of poor management and cleaning of the motorcycle.

As a responsible owner, you should take the time out, at least once every 2 to 3 months, to inspect and clean your motorcycle.

Parts such as the fuel filter and the carburetor require frequent cleaning to prevent overworked and causing issues.

Engaging regular cleaning will prevent backfiring from occurring and boost the performance of your motorcycle.

It is best to make this a habit so that you can get into the groove of how to clean your bike and do the cleaning more efficiently and quickly as time goes on.

2. Frequent Trips To The Mechanic

Regular inspections from the mechanic go hand in hand with regular cleaning. You can combine the two as well.

However, the main reason why you should go to a mechanic every 3 to 4 months is so that he/she can inspect the motorcycle for any defective or damaged components so that they can be replaced or fixed before causing bigger issues.

If they discover any defective component or damaged by chance, they can fix it then and there, saving you the trip. You can even ask them to clean the motorcycle and save yourself the effort.

Regular servicing will also prevent the motorcycle from backfiring and improve the health and life of your motorcycle overall.

3. Proper Motorcycle Upgrades And Fuel

Any upgrades and changes to the fuel system that you make sure of should be done carefully and with proper planning as changes to the bike’s fuel system can have adverse effects on the exhaust or the system, leading to motorcycle backfiring.

Also, make sure that the fuel you use is high quality. If you are using low-quality fuel, you should switch to a good-quality brand to avoid the problems associated with it and get the most out of your car.

Upgrades to the bike, in general, should not be made lightly and should undergo a lot of planning before you purchase any upgrades.


Backfiring in motorcycles is a very common issue due to the variety of reasons that can cause it. Frequent backfiring can cause major damage to the engine, which may eventually lead you to replace it entirely.

However, each of these issues has its fix, which is relatively easy and can save you a lot of money in the long run.

After reading this article, I’m sure you should be able to answer why does my motorcycle backfire and be able to isolate the problem and figure out the best approach to resolving it and incorporate the tips mentioned above to further improve the health and life of your motorcycle.

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