Contrary to popular belief, straight pipes are bad for a motorcycle and for the rider as well. Why? In a nutshell, the five major counter-arguments against straight pipes (a.k.a. cutting out the mufflers) are as follows:
- Possible engine damage
- Engine re-tune may be required
- Risk of other possible damage
- Disturbing others (straight pipes are very loud)
- Risk of damaging your ears
- Legal issues
If you want to find out more about the potential risks of straight pipes, this post is for you.
We at PowerSportsGuide have compiled everything you need to know to keep your motorcycle safe and legal!
What Are Straight Pipes on a Motorcycle?
Simply put, straight pipes on a motorcycle are a special type of aftermarket exhaust system. As its name suggests, straight pipes provide a completely open system that doesn’t feature any mufflers. Straight pipes on a motorcycle appear in two different forms. Some owners just remove the mufflers while others replace the whole system with an aftermarket straight pipe exhaust. Since these systems are recommended for drag racers, they are also known as “drag pipes.”
This is a common modification on cruiser motorcycles powered by large V-twin engines. But as you will see, a straight pipe can be harmful or even illegal in most cases!
Riders install straight pipes on their bikes for many reasons, but the most important ones are arguably as follows:
- To get a better and louder sound (the most important reason)
- Aesthetics considerations (many riders prefer to customize their machine)
- To get more horsepower
- Reduce the overall weight
Without further ado, let’s get down to the nitty-gritty and take a closer look at these factors!
Is a Straight Pipe Bad for Your Motorcycle?
Yes, it’s a lesser-known fact that straight pipes can be bad for your motorcycle in many ways. We are no longer in the ‘60s or ‘70s when motorcycles were very simple machines. Instead, their exhaust system is a very important part of the machine, the result of precise engineering. Removing or modifying it may cause damaged exhaust valves or other severe malfunctions.
Do you have any doubts? Keep reading!
1. Do Straight Pipes Damage Motorcycle Engines?
Yes, straight pipes can damage motorcycle engines, even if the chances are small. Keep in mind that straight piping your bike can cause various types of damage to the exhaust valves, especially if the pipes are too short. This is because if you suddenly leave the throttle, hot exhaust gases are pulled out from the pipes while cold air flows directly to the valves. (This issue is known as “cold air reversion.”)
If cold air hits hot valves, it can crack, brake, or even bend the valves. What’s more, in a worst-case scenario, the valves can be sucked into the engine.
And as you can assume, any of these issues may end in very pricy repairs.
These risks exist mainly when the muffler is simply removed, and the remaining pipe proves to be too short. (On the other hand, a custom “straight pipe” exhaust system can also cause similar problems if it’s too short and has a diameter that is too large.) Also, without a muffler a motorcycle is prone to backfiring.
2. Engine Re-tune May be Required
Besides the potential for valve damage, straight pipes can cause higher fuel consumption and many other malfunctions as they change the system’s dynamics.
The exhaust system of the newest motorcycles is a very sophisticated part of the machine. They are designed to handle the different amounts of gases and resonance at different RPMs.
Therefore, straight pipes can affect engine performance and efficiency in many ways. For instance, they can cause the engine to run too lean or rich because of the loosed back-pressure.
Long story short, if you are considering installing straight pipes keep in mind that additional engine tune ups may be required.
3. Other Possible Damage
Besides the above-mentioned risks, straight pipes can damage your bike or even your gear in some other ways. Let’s face it, stock motorcycles always come with mufflers for many important reasons.
They not only play an important role in the proper operation of the engine but also move gases away from both the bike and the rider.
While stock exhaust systems and “long” straight pipes do this job quite well, poorly designed or pipes that are too short can be dangerous. The inefficiency of these pipes can lead the rider to inhale some exhaust fumes, especially when the bike is idling.
Another drawback of straight pipes is that they tend to be very hot. In extreme cases they can melt the bodywork or damage the rider’s clothes or boots.
4. Why Are Straight Pipes So Loud?
Although many riders enjoy the sound of straight pipes, let’s face it, they are extremely loud.
The brutal noise of these bikes can wake up neighbors, scare children and dogs, or just simply disturb other citizens.
What’s more, since these motorcycles are significantly louder than any other vehicle out there, many other drivers and pedestrians find them very annoying.
Consequently, even if these riders think they are cool, they typically get a lot of hate from others. The only people who appreciate loud straight pipes are some other petrolheads, which is a very small community.
That’s why most states have legal noise limits to restrict loud motorcycles!
Are you wondering whether straight pipes are legal on public roads? Let’s drill into the details.
5. Are Straight Pipes Illegal on Motorcycles?
To the delight of many citizens (and the regret of many riders), straight pipes are illegal on motorcycles in most states. But even if your state doesn’t prohibit them, don’t forget that many cities and local governments may have local restrictions as well. So, if you are considering straight piping your bike, besides state laws don’t forget to check local regulations.
If your bike is too loud or features illegal modifications, you can easily get in trouble with the law. On top of that, even if you’re completely legal, beware that police are prone to following and stopping loud motorcycles!
6. Damaging to Your Ears
Last but not least, you shouldn’t overlook the potential health risks of a loud exhaust. Did you know that if you’re exposed too long to a noise intensity at or above 85 dB you may end up with permanent ear damage? And, sadly, motorcycles with straight pipes can far exceed this limit.
Just do some research on cruiser forums, and you will be surprised how many riders have hearing loss from loud straight pipes. As they say, once hearing goes, it won’t make a comeback.
To prevent this, many of them use earplugs.
As you already know, straight piping your motorcycle can damage it in many ways. If it’s too short, it can cause exhaust valve damage and other engine malfunctions. Furthermore, straight pipes are extremely loud, which is why they are illegal in most states and cities. Moreover, they are not only very disturbing but can also damage your ears. Therefore, this modification is definitely not recommended, even if it’s easy to do!
If you want to customize your bike to make it sound better, you should consider investing in an aftermarket (street-legal) exhaust.
Many of these provide a nice sound but put out much less noise compared to straight pipes.