So we know that to get more power on our bikes, we want more air. We also know that air flow is heavily restricted by the air filter in the air box. Crazy idea – what if we remove the airbox completely?
Will motorcycles still run (or even start) without an airbox in place? This question is asked surprisingly a lot of times.
For a quick answer – yes, your motorcycle will start and can still run (at limited capacity) without an airbox on – although I don’t recommend you to do that. Your engine will run lean and get damaged from the impurities and dirt that could enter.
Now the TLDR is out of the way, let’s talk in much more detail about airbox and motorcycle performance in general.
After reading this article, you will understand all about airboxes, air filters and why you shouldn’t remove them from your motorcycles. As a bonus, we will also talk about the much better ways to improve bike performance.
Ready? Let’s go.
What’s The Role Of Airbox In Motorcycles?
Airbox is the entrance for air to enter into your bike’s engine for combustion. Airbox includes an air filter – responsible for trapping air impurities and dirt from entering the engine.
If you don’t already know, a motorcycle generates power by mixing air and fuel to create combustion.
This combustion is an explosion that moves pistons in your bike’s engine – causing it to move forward (very simple explanation).
When it comes to airboxes, the air filter is the key component. When you remove an airbox, the majority of problems come from not having an air filter. I will talk more about the problems later.
On some motorcycles, airboxes are also designed by manufacturer in a way that it muffles engine sound – basically to make your motorcycles quieter.
Why do manufacturers want quieter bikes? Good question – just 2 reasons:
- To comply with laws and regulations in the area
- Not all riders are enthusiasts like us who like loud engine noises
What Happens If You Remove Airbox From A Motorcycle?
Many beginners think that removing airbox from a motorcycle will give them a boost in horsepower. This is not true – but why do they think this way?
Earlier I said, motorcycle engines use a mixture of air and fuel to generate combustion (explosion) and deliver power.
And if you want more power, you need even more air and fuel to generate bigger combustions. This is true. However, keep in mind that you need more of both air and fuel (not just air).
By removing the airbox from a motorcycle, you will oversupply your engine with too much air but still the same amount of fuel.
This messes up your combustion – causing your bike to run lean, sluggish and with reduced power.
This is just the most common problem. Let me list all the things that happen when you remove the airbox from your motorcycle.
1. Slightly Louder Sound
As I said, some airboxes are designed by manufacturers to also muffle engine sound. If you remove them, then you can hear more from the engine.
I wouldn’t say it’s significant but it could be noticeable at lower speed. I don’t recommend you remove the airbox to get the louder sound though – it’s not worth it!
Go on to the next points to see what I mean.
2. Engine Runs Lean
Without an airbox in place, you won’t have an air filter. Suddenly, your engine is receiving way more air than it needs.
You see, to ensure a perfect and powerful combustion, the amount of air and fuel in the combustion chamber must be at the right ratio – typically 14.7 : 1.
That means 14.7 KG of air is needed to burn 1 KG of fuel.
By removing the airbox, you are only increasing the amount of air. If the amount of fuel remains the same, the air to fuel ratio is skewed and your bike will run lean.
Running lean is not ideal and can be dangerous. First thing you notice will be how hot your engine becomes. Lean mixture causes combustion to be very hot.
Running lean also decreases power output. It would be ironic – removing the airbox to gain power but instead you lose it and potentially damage your engine in the process.
If you are interested to learn the details in running rich vs running lean, then give my other article a read – Is It Better To Run Rich Or Lean On Motorcycle?
3. Wear And Tear Damages To Engine Interior
Did I already mention removing an airbox means removing the air filter along with it?
Air filters are designed and installed for a reason – to keep impurities like bugs, dust and dirt in the air from entering the engine.
Without the air filter (or airbox), these air impurities will enter the engine and accumulate. In the best case scenario, your internal engine walls and pistons will have some scratches.
At the worst case scenario, you will have engine failure that costs a fortune to repair.
4. Inconsistent Throttle Response
Without an airbox, you will not get that smooth throttle response that you are used to on a typical bike.
Very intelligent people work together to design and create those airboxes on your motorcycles. They are packed with science and physics to make sure power delivery is consistent.
Removing it will skew the dynamics that are in place inside your engine – causing inconsistencies like incorrect throttle response.
5. Traffic Ticket
Did I also tell you that removing the airbox from your motorcycle is illegal? Depending on where you live and cops on duty, you could get a traffic ticket from that.
If you are living in strict US states like California, then it’s just a matter of time before you get a ticket.
What About Drilling Holes On Airbox?
Drilling holes on airbox is another thing that’s discussed a lot. The goal is similar – by drilling holes on your airbox, you could potentially get more air flow.
This is another thing that I don’t really recommend. You won’t get any significant performance gain out of this one (maybe none at all).
Here’s an article I wrote about this topic. Can I Drill Holes On My Motorcycle Airbox?
Better Ways To Improve Air Flow In Motorcycle
Pod Air Filters
Pod air filters are basically air filters without the airbox. They are completely exposed and are less restrictive – which means they allow much more air to enter, while also filtering out the dust in dirt in the air.
Rather than just removing the airbox and risk messing up your bike, you now have the best of both worlds – no airbox (more air flow) but still have an air filter in place.
These pod air filters are not expensive – about $25 from Amazon. And they are also not too difficult to install. I am sure you can find tutorials on YouTube.
“Sounds great!” – Is that what you were thinking? Of course you do. They are great but there are also some cons to these pod air filters.
After installing these pod air filters, you will need to bring your bike for a tune – either rejetting the carb or purchasing a Power Commander if your bike uses a fuel injector.
This is not really a con though. If you are serious about power and want your bike to run well, you need to give it more air (pod air filters) and also more fuel (tuning). Just increasing one without the other won’t work.
The other con is the fact that it’s open – great for air flow but not so great if it rains. This really depends on the bike you have. If the pod air filter is completely exposed, then you have to make sure rain water doesn’t get in – or worse, mud.
The fix is quite simple though, you just need a pod air filter cover. And don’t ride your bike for too long under the rain.
The other better way to improve airflow is the good old performance exhaust . I am talking about a full system exhaust and not the slip-ons – these are great for looks and sounds but not for power.
A full system exhaust is quite expensive – where $1,000 is a common starting price. However, if you really want performance, a full system exhaust will deliver.
Also don’t forget to tune your engine after installing a full system exhaust. They tweak the exhaust flow and airflow significantly.
You need to inject much more fuel to keep up and unlock the exhaust’s full potential. I have an article discussing exhaust here
Check them both out and learn even more. Cheers!