Do I Need to Retune My Motorcycle With A New Exhaust?

This article discusses the need for retuning your motorcycle when installing a new exhaust. 

It is common knowledge that you need to retune your motorcycle if you swap out the stock exhaust for an aftermarket pipe. But why do you need to do this? What is tuning in the first place? And can you get away with not turning a motorcycle when adding a new exhaust? 

If you are asking any of these questions, we’ve got you covered. First, we’ll explain what a tuning is, how it works, and if you need it for your motorcycle. Then, we will look at different exhaust types to see if you need to tune your bike with them. 

Throughout our motorcycle riding career, which spans almost two decades, we have swapped a million different exhausts. Our extensive experience provides us with the right information so you can swap the exhaust on your motorcycle easily.

Keep reading for more info. 

What Is Tuning?

For the uninitiated, tuning a motorcycle engine simply refers to changing the ratio of air and fuel the engine uses. This is necessary if you add some new performance parts such as exhausts. 

Different motorcycles are tuned in different ways. Generally, older motorcycles are tuned via the carburetor. Newer models may use an ECU that controls the ratio of air and fuel in the engine. 

Why Is Tuning Required?

Tuning a bike is necessary if you add a new exhaust to it. The new exhaust allows for the free flow of exhaust gasses, so the stock tune doesn’t allow for optimal engine performance. 

If you don’t tune your bike after adding a new exhaust, it could exhibit several different symptoms. Firstly, the bike may feel sluggish and low on power. Fuel mileage may become worse. You might even notice the bike start to smoke from the exhaust. 

So now that we know what tuning is and why it is necessary, let’s discuss when you need to tune an engine and when you don’t. 

Tuning Is Not Required For Slip-On Exhausts

When swapping out the muffler for a new slip-on exhaust, you don’t need to tune your motorcycle. This is because a simple slip-on does not make that big a difference in terms of the air-fuel ratio of the bike, so retuning the engine is unnecessary. 

Tuning Is Required For Full System Exhaust

On the other hand, tuning an engine is necessary when you add a full system exhaust to the bike. When you do a full system exhaust swap, you significantly change the air-fuel ratio. 

Specifically, a full system exhaust system allows for a higher flow of exhaust gasses. This increases the amount of oxygen being sucked in by the engine, while the amount of fuel being injected is the same as before. 

When tuning a full system motorcycle exhaust, you increase the amount of fuel injected into the engine to match the amount of air. This balances the air-fuel ratio again and gives you a better riding experience. 

Why Do I Need To Retune My Motorcycle with a New Full System Exhaust?

New full system exhausts are installed on bikes to add power and make the bike louder. Depending on the exhaust, you can also enhance the bike’s sound to be higher pitched, deeper, or crisper. 

All of this is achieved because of the higher volume of exhaust gasses being emitted by the exhaust. But without a new tune to go along with the new exhaust, you could lose power rather than gain any! 

Furthermore, you won’t get as dramatic a difference in sound either. And the new exhaust could even cause your bike’s mileage to drop significantly. 

How To Tune A Carbureted Engine?

If you have an older motorcycle, odds are it is carbureted. Tuning a carbureted engine requires adding new jets to the carburetor, which change the amount of fuel being delivered to the engine. 

Carburetors are entirely mechanical, and you don’t have to fiddle around with computers to tune a carbureted motorcycle engine. 

How To Tune A Fuel Injected Engine? 

Tuning a fuel-injected motor is a lot different than tuning a carbureted engine. In a fuel-injected engine, computer-controlled sensors govern how much fuel is being delivered to the engine. These systems are significantly more efficient than carburetors as they can inject fuel in the exact amount needed for optimal combustion. 

Carburetors, by comparison, are less accurate and more prone to issues. 

To tune a fuel-injected engine, you will need to flash the ECU via a complicated computer program. With the new full exhaust system installed, this program tells your bike’s ECU how much fuel injection is necessary. Your bike’s power output is also measured with a dyno to see if the new tune is effective. 

A power commander can also be used to tune a motorcycle engine. This device connects to the bike and lets you customize the air-fuel ratio. Depending on your requirements, you can install different ‘maps’ or settings for the air-fuel balance. 

The power commander method is a bit cheaper than taking your bike to the shop and getting it dyno-tuned. However, you will need a bit of technical know-how to get it done. 

You will probably want to put the bike on a dyno anyway to check if the tune is effective. An ECU flash will also be done by professionals who better understand the inner workings of a bike, so maybe it’s the better option. 

How Much Horsepower Does A New Exhaust And Tune Add?

It depends on the exact bike and the full system exhaust you go for. Several different fuel maps and power commander settings allow for better performance or better fuel mileage, etc. In practice, you can expect anywhere between a couple of horsepower to almost a 10 horsepower increase with a new tune!

Conclusion

Tuning a motorcycle engine is necessary whenever you add a full exhaust system. If you don’t want to fiddle around with carbs and ECUs, maybe get a slip-on instead. But if you get a full system, a tune will unlock extra HPs, louder sound, and possibly better fuel mileage.

Author
Higgins Cooper1

Hi, I'm Hugo, I'm a motorcycle enthusiast who’s been riding for the last 10 years. I'm passionate about all things motorcycles and started Bikes Future to help other riders make the right motorcycle moves. I ride a white Kawasaki Ninja 400, and enjoy adventure riding on country roads when I get the chance.