Every rider wants that sweet motorcycle growl but not many have the budget for a full system exhaust. Back in the day I was one of these riders – love the sound but broke!
Which is why I did plenty of research on the topic. To my surprise, drilling holes on motorcycle exhaust is quite popular.
In this article I will share with you the things I researched with added knowledge from my experience.
Drilling holes on motorcycle exhaust is actually a great and cheap method to make a motorcycle sound louder.
The key is to drill holes 1-by1 on the muffler till you are satisfied with the sound. Add a little paint on the holes to prevent rusting.
I have tried it myself and the sound improvement was definitely noticeable. However, there are still many points to consider – things like engine damage, backpressure and is it even legal?
So get a cup of coffee, relax and read on.
How Does Drilling Holes On Exhaust Make Motorcycle Louder
Drilling holes on motorcycle exhaust allow sound waves to escape before they are silenced by the muffler. This results in a noticeably louder motorcycle sound – both during idle and acceleration.
I am guessing you already know that a motorcycle engine uses combustion to move the wheels and this combustion produces loud sounds that get silenced by the muffler or baffles located in the exhaust.
Drilling holes on motorcycle exhaust allows some sound waves to bypass the muffler and go straight out.
Of course, you need to drill holes in the right spot – this is very important and I will cover it later. Drilling holes on incorrect spots can cause problems like inaccurate O2 reading – causing CEL and incorrect air/fuel ratio.
Will Drilling Holes On Motorcycle Exhaust Cause Damage?
Drilling holes on motorcycle exhaust will not cause any engine damage. The holes are drilled at the very end of the exhaust and the backpressure decrease is likely not significant enough to impact air/fuel ratio.
When it comes to drilling motorcycle exhaust, the main concern is always engine impact from the decrease in backpressure.
Quick recap – backpressure is the pressure coming from exhaust. A change in backpressure could impact the amount of air in the combustion chamber.
Which means, if backpressure is changed significantly, your air/fuel ratio will also change and you will be required to tune to fix this issue (it’s not cheap!).
But fortunately, you don’t have to worry about this. Drilling small holes at the very end of the exhaust system will not cause such a significant impact.
Just make sure you don’t go overboard when drilling the holes – keep them small in size and number. I will talk more about this later when I cover how to do it.
The damage that you should be more worried about is rusting. Drilling holes on exhaust can cause rusting – this won’t cause severe damage but still undesirable nonetheless.
To counter this, make sure to apply an anti-rust spray to the holes that you drilled – this is an effective way to prevent rusting. You could also use a regular spray paint to prevent rust.
Steps To Drill Holes On Motorcycle Exhaust For Sound
Drilling holes on motorcycle exhaust for sound is pretty easy. It’s all about drilling small holes with a ¼ inch drill bit at the end of the exhaust (the muffler).
Drill one hole at a time because you can’t reverse a drilled hole!
Things you need to drill holes on motorcycle exhaust:
- A drill
- ¼ inch drill bit
- Anti-rust spray
If you don’t have a drill, borrow one from a friend! Drilling holes on exhaust should be a quick and cheap method to improve sound. Don’t make it expensive.
NOTE: You don’t have to remove the exhaust from your motorcycle to do this.
Steps to drill holes on motorcycle exhaust:
- Identify the location to drill. This should be at the very end of your exhaust tail pipe. Drill holes around the exhaust outlet.
- Drill 2 parallel holes around the exhaust outlet.
- Go for a ride and test the sound
- If not loud enough, add another 2 holes (max 8) and repeat step 2 and 3
- Apply anti-rust spray on holes
Here’s a great YouTube video showing you exactly how to drill the holes.
Is Drilling Holes On Motorcycle Exhaust Legal?
There’s no law about drilling holes on motorcycle exhaust. However, in certain strict states like California, a motorcycle is limited to produce a sound of 88 decibels. Anything louder than this is illegal.
Knowing this, I suggest you check the laws and regulations in your area before you attempt to do this mod.
When you decide to drill, I recommend you don’t go overboard. Just drill enough holes to give you a more aggressive growl. I went for about 4 holes and it was noticeably louder.
Maybe you would feel the same.
Will Drilling Holes On Motorcycle Exhaust Void Warranty?
Some riders are also curious if drill holes on motorcycle exhaust will void its warranty. The answer is both yes and no.
By drilling holes on your exhaust, you will definitely lose warranty on the exhaust but not other parts that are unrelated like headlights or battery. Unless of course, they can prove that your modification is a direct cause to the issue.
If your motorcycle is brand new, I wouldn’t suggest you drill holes in them yet. Just wait a bit and consider other options before you make a permanent change and lose the warranty!
Cheap Ways To Improve Motorcycle Sound
If drilling holes is not your thing, then here are the alternatives to still give you a louder motorcycle sound.
1. Remove Exhaust Baffle
Exhaust baffle is a tube located inside a motorcycle muffler. Their job is to cancel out sound waves and silence them before they exit.
Removing the exhaust baffle from your muffler can significantly make your motorcycle louder. Motorcycle baffle is the primary way to silence sound in motorcycles. Removing them means your motorcycle’s silencing effect is reduced significantly.
Here’s an article I wrote related to this topic. Running Without Motorcycle Baffles: Is It Bad?
2. Straight Pipe
Straight piping means removing all the components from your mid pipe and back. This includes removing catalytic converters and mufflers.
By straight piping, you completely remove the sound suppressing mechanism from your motorcycle. You can expect your motorcycle to be significantly louder – in fact, too loud.
You could straight pipe yourself. It involves cutting off the exhaust pipe using a drill. But it’s best to leave this to the pros. Incorrectly cutting off pipes may cause other unintended damages.
I don’t really recommend straight piping because it’s 100% illegal and horrible for the environment. Here’s more information about straight piping.
Is Straight Piping Bad For Your Motorcycle?
3. Pod Air Filters
Pod air filters are aftermarket air filters that are more open and exposed. A pod air filter replaces your motorcycle’s airbox.
A motorcycle airbox is designed to also silence engine sound. Removing the motorcycle airbox in place of pod air filters can make your motorcycle sound louder.
However, it will not be significant enough like removing exhaust baffle.
Pod air filter is actually a performance mod. A louder motorcycle is just one of it’s side effects. Pretty good for a side effect huh?
4. Slip On Exhausts
Slip on exhaust is an aftermarket exhaust that’s defined specifically to improve the look and sound of a motorcycle – it will not improve performance.
A slip on exhaust replaces the end portion of the exhaust – it’s also known as “the end can”. This replacement includes a new muffler and exhaust tip.
The new muffler included is usually designed with sound in mind. Which means, you can expect a great sounding motorcycle after the installation.
I highly recommend going this route if you really want a better sounding vehicle. The other mods above like removing baffle or drilling holes can help you get a louder sound. But a slip-on exhaust can give you great sound (not just loud).
A slip-on is also not expensive. You can get one under $100 (without installation). And don’t worry about having to tune. A slip-on exhaust is not significant enough to require tuning.
Drilling holes on motorcycle exhaust is one of the cheapest and effective ways to make a motorcycle louder.
However, this change is permanent and you risk other factors like rust, losing warranty and being pulled over if the sound is too loud.
To be safe, I recommend saving up and getting a slip-on exhaust instead. They are not that expensive, look good and will definitely give you a good growl.
Here’s a related article about slip-on exhaust that you might be interested in. Do You Have To Tune Motorcycle After Installing Exhaust?
I hope this article has been useful to you. Till next time.