Drilling holes on airboxes are nothing new – especially in the car and motorcycle world. People say you could gain a few extra horsepower and better sound just from this simple hack. 

Is this true for motorcycles? That’s what we will be discussing in detail today. What are airboxes even? Could we even remove it? 

TLDR – drilling holes on a motorcycle airbox will not give you any noticeable horsepower.

You will end up with the same power, a little louder sound and damaged airbox that could let rain water and mud in. Don’t do it.

Let me explain more.

What Does a Motorcycle Airbox Do?

A motorcycle airbox allows air to enter from outside into the combustion chamber – which is then used to create combustion and generate power for the motorcycle. 

In case you don’t already know, motorcycle engines are combustion engines. Which means they create small explosions (combustion) to generate power and move the wheels. 

Combustion requires both air and fuel to create. Fuel is injected into the combustion chamber. Whereas air is sucked from the surrounding (through the airbox).

Open up the airbox and you will find the air filter. Air filters make sure impurities like dust and bugs do not enter the combustion and cause problems.

motorcycle airbox

Motorcycle airbox is usually located in the mid section below the seat.

People suggest drilling holes on your motorcycle airbox to allow more air flow. Theoretically, the more air you have in the combustion chamber, the more power you will get.

This is because more air results in a bigger combustion – which means more horsepower. This works well in theory but not so much in real life.

Let me tell you why.

Why You Shouldn’t Drill Holes On Motorcycle Airbox?

1. No apparent power gain

The power gain from just drilling holes from your airbox is minimal – even none in most cases. The increased air flow is not as big as you think.

This of course depends on the size of the holes. However, you are not supposed to drill such big holes because rain water or mud could easily get in and ruin your engine.

2. Needs tuning to calibrate

Even if you manage to get significantly more air into the combustion chamber, you need to bring your motorcycle to a tune. Otherwise, you even risk running lean. 

An optimal combustion requires the right amount of air and fuel. Too much air and your engine will run lean – losing horsepower and overheats. 

Whereas too much fuel and your engine will run rich – causing unburnt fuel to escape from the exhaust and lowering your fuel economy. 

Modern motorcycles that use fuel injector can tune their motorcycles by using a Power Commander. Older motorcycles that use carb will need to tune by rejetting their carb. 

The goal of tuning is to increase the amount of injected fuel. You will only gain extra power if you have more air and fuel. 

You can check out this article where I talk much more about tuning. This article refers to tuning when replacing exhaust. However the same theory applies. 

Do You Have To Tune Motorcycle After Installing Exhaust?

3. Mud or rain water can get in

With holes on your airbox, it’s only a matter of time before rain water, small rocks or any other things getting in. 

Most of the time, you should be fine because your legs and thighs will be covering the air box anyway. However, they can still happen. 

And once this happens, you could damage the interior of your engines – wear and tear damages at best and engine failure at worst

If you really want to do it, I suggest you drill holes on the top part. Drilling holes on the bottom impose more risks to stuff like mud and rocks. 

4. Voids warranty 

If your bike is new, drilling holes on the airbox will definitely void your motorcycle warranty. However, it should not void all (only areas that are impacted by the airbox).

Warranty for things like electrical should still be fine. 

This is because of Magnusson-Moss Warranty act – which protects consumers from invalid warranty terms. 

I cover more about Magnusson-Moss Warranty act in my other article. You can check that out. Does Muffler Delete Void Warranty? 

5. Louder sound

An airbox is also designed to muffle the sound of an engine. Drilling holes on it will cause sound waves to escape prematurely. 

This causes your engine to sound louder. Not necessarily sound better though. It’s just a little louder (don’t expect so much). 

This point can be a pro or a con – depending on you.

How Much Power From Drilling Holes On Motorcycle Airbox, Really?

Not much, really. If you are lucky enough that your engine runs a little rich out of the box, then maybe you could gain 1-2 horsepower.

Otherwise, drilling holes on the airbox alone will not yield you any horsepower. 

You are more likely going to run lean (because of the extra air) and risk having junk entering your combustion chamber through these holes.

Alternative Instead Of Drilling Holes On Airbox

Instead of drilling holes and risking running lean and engine damage, here is a list of things you could do instead – some for sound and some for power.

1. Full system Exhaust

Full system exhaust is where you replace the entire exhaust system – beginning from the midpipe till the exhaust tip. 

If you are serious about getting more horsepower for your bike, this is the best choice. A full system exhausts significantly improves the way exhaust gases flow in the motorcycle. 

Add it with tuning and you will likely gain additional 10 horsepower plus a much better sound because a new muffler is also included. Not bad at all – definitely noticeable change and worth the money.

Motorcycle full exhaust system

Full system exhaust

2. Slip-On Exhaust

Slip on exhaust is where you replace just the end portion of your exhaust system – this includes a new muffler and exhaust tip.

You won’t get any significant performance gain from this mod (maybe nothing at all). You should go for this option only if you don’t care much about performance and want an improved sound and overall look.

Worth pointing that you won’t need a tune with this mod. The change in airflow is insignificant. So don’t worry about running lean or messing up the air/fuel ratio.

Slip-on exhaust

Slip-on exhaust

3. Performance Air Filter

Performance air filter is less restrictive than a stock air filter. The most popular brand (K&N) uses oil to trap impurities while still allowing much more air to pass through. 

If you insist on wanting more air into the combustion chamber, then a performance air filter is a much better choice than drilling holes on your airbox.

But note that a performance air filter alone will not yield you much result. Enthusiasts usually pair this up with a full system exhaust and tune. 

Motorcycle performance air filter

Cone-shaped Performance air filters like K&N replaces the entire airbox

Ifandi S.

Ifandi S.

Passionate about everything mechanical. Ifandi has been involved with motorcycles and cars since the old days - in his family's auto parts shop. Want to keep in touch? Scream "STRAIGHT PIPEEEEE" at the top of your lungs and Ifandi will show up.

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