How to tell if your motorcycle has an exhaust leak

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The motorcycle’s exhaust is an important feature. The way it looks and the way it sounds has a lot to do with the owner’s style and how they want to express themselves while out on a ride.

No matter how the exhaust is arranged, any rider can experience an exhaust leak. It is difficult to diagnose exhaust leaks because they involve gases that are hard to see.

How do you know if your motorcycle has an exhaust leakage? Listening to unusual popping sounds from the motorcycle’s headers, as well as strong exhaust odors are two of the best ways to determine if it has an exhaust leak. To check if the exhaust is leaking, you can use a paper towel or other light object to hover over it.

Exhaust leaks are a common problem on motorcycles that I own. I’ve owned 13 of them and often ran into this issue. This article will explain exactly how you can diagnose an exhaust leak, how to fix it, and other information you’ll probably want to know.

How to tell if there is an exhaust leak

Due to similar symptoms, exhaust leaks can sometimes be mistaken for other problems. If you suspect an exhaust leak on your bike, it’s important to promptly take care of the issue to ensure it runs well and to ensure your personal health.

You can tell if your motorcycle has an exhaust leak by its sound. Exhaust leaks most often occur where the header connects to the engine. If you have a loose header, you’ll likely hear a popping sound. Sometimes, this could mean that the engine is going down. An exhaust leak could sound like the valves tapping. A large leak will produce a louder sound, while a smaller one will make a subtler sound.

Sometimes hearing that popping sound isn’t enough to determine whether or not this is your issue. If you do hear a popping sound but aren’t sure if it’s the exhaust causing it, try turning on your bike while it’s cold and listen to the characteristics of the popping sound. An exhaust leak will likely make a louder popping sound when it’s first turned on and subside as the engine gets warmer.

This is an indication that the exhaust header bolts may be loose. Your gasket surface and your flange surface on the exhaust header aren’t fully touching when the motorcycle is first turned on. As the motorcycle warms up, the gaskets expand and seal the leak.

If the motorcycle is running and the exhaust is coming out of the headers, this is another way to determine if there is an issue. I don’t recommend you use your hands since they can be extremely hot. Instead, you can use a paper towel or something lighter like a paper towel. You can hover the towel around the headers of the engine to check if it is leaking.

Also notice the smell of any exhaust while you’re idling on the motorcycle. There’s usually a small whiff of exhaust anytime you’re riding, However, if there is an excess of it or a strong odor, this could indicate an exhaust leak.

It’s not impossible to get an leak somewhere random on the exhaust header pipes though it’s much less likely than having a leak where the header connects to the engine.

Pin holes can form but it’s unlikely because water doesn’t stand much of a chance inside headers due to the constant heat going through them (unless your motorcycle has been sitting for a while). You can also use the paper towel to identify pinholes in other headers.

It’s more possible to have holes in the muffler. Your exhaust will be louder if there are holes in the muffler. However, it will not make the same popping sound as the headers. This usually doesn’t cause much harm.

What Causes A Motorcycle Exhaust Problem?

Motorcycles that have been heavily used or older models are more likely to experience exhaust leaks. It is important to understand the cause of the leak so that you can take proper care of your bike in the future.

As we have already mentioned, the most likely place for exhaust leakage to occur is between the connection of engine and header. It is common for the exhaust bolts to become loose during ride vibrations. So really, it’s more of a wear and tear issue.

If the leak isn’t due to a loose bolt, the second likely culprit is a faulty gasket. Not all motorcycles have a gasket between the header and the engine, but a lot do so it’s worth checking out how well it’s holding up if you’re having this issue.

Pin holes can also be caused by corrosion, mostly from rust. This happens when your motorcycle sits for too long and allows rust to accumulate in the exhaust system.

Are Exhaust Leaks Bad for My Motorcycle?

Once you find that a motorcycle exhaust leak is happening, you’ll need to take care of the issue as soon as possible. Many people are unsure if an exhaust leak is dangerous for their motorcycles. Exhaust leaks aren’t good for the bike, which is why it needs to be addressed promptly.

The exhaust will heat up from wherever it leaks. The piston pressure is pushing all that hot air out and it is spreading instead of evenly across the header pipe and out the exhaust. It can also warp metal due to the heat.

Extreme heat can cause exhaust headers to change colors, most likely yellow or blue. Though the color change is fixable, it’s annoying to deal with and is best to be avoided in the first place. You can read my article here about why exhaust pipes on motorcycles turn blue.

An exhaust leak on a motorcycle can also impact it’s performance. You won’t have as much power and you may notice your motorcycle acting slightly sluggish.

Fluid dynamics refers to the exhaust leak as a discontinuity in the air flow. The system is affected by any discontinuity in the flow of air. This is due to frictional losses, which are manifested by engine performance. In other words, an exhaust problem could make the motorcycle run slower depending upon its severity.

It’s also bad for you as the rider if there is an exhaust leak on your motorcycle. There are noxious gases leaking right underneath you and can be very dangerous if you’re breathing those in. You’re essentially inhaling carbon monoxide; that’s why exhaust is routed to the back of the bike away from the rider.

How to fix it yourself

Though this is an issue that should be addressed promptly, it’s actually a fix that most people can perform themselves and is inexpensive most of the time.

You should first address this issue by tightening the bolts connecting to the engine and headers. If they’re already tight, don’t over tighten them because doing so could cause damage to the engine (which would be an expensive to fix). Make sure to check your manual for torque specs to make sure the bolts are the right resistance.

If the torque specs on the header bolts are correct but you’re still having an exhaust leak, either the headers are placed in a little crooked, the gasket needs to be replaced, or the header itself may have warped so much that you need to get new ones.

Make sure you have a replacement gasket when you install a header. Gaskets are usually very inexpensive and will ensure you’ve covered all your bases when making a fix like this.

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