How to Fix Blue Motorcycle Exhaust Pipes

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Motorcyclists love to display their motorcycles every time they take off on a ride. And it’s no wonder because motorcycles are fun vehicles that can look pretty amazing if you take good care of them.

Motorcycles can have a few cosmetic problems, which can sometimes be irritating. Exhaust pipes that turn blue due to no apparent reason may be one of these issues. Not only is this annoying, it’s also embarrassing.

Why do exhaust pipes from motorcycles turn blue? The extreme heat that passes through motorcycle exhaust pipes causes them to turn blue. This is often caused by motorcycles running lean. In other words, too much or too little gas is mixed together. This causes exhaust pipes to become blue.

I’ve run into my fair share of blue motorcycle pipes during my restoration days. As inconvenient as they are, it’s possible to get rid of it as well as take preventative measures to keep it from happening in the first place. This is what I’ve learned about the process.

Your exhaust pipes are turning blue

The exhaust system of a motorcycle serves two purposes. It can be used to make a statement and provide a vital function for the bike. The exhaust system is often the first thing that someone will customize if they are looking to modify their motorcycle.

Because they’re so important to the cosmetic makeup of a motorcycle, owners usually pay special attention to how they look and start to worry and become annoyed when they start to turn a color that’s unintentional. Some people like the discoloration, but some don’t.

It’s actually pretty common when the exhaust pipes on a motorcycle turn blue, so don’t feel bad if you’ve become a victim of this phenomenon. Extreme heat can cause motorcycle exhaust pipes to turn blue. Obviously there’s already a good amount of heat passing through them, but if there’s an excessive amount or a hotter amount passing through, the result often ends with blue pipes.

Motorcyclists who rev the engine often may notice that their pipes eventually turn blue. The engine will work harder when you rev it up, which can lead to excessive heat passing through the pipes. Though revving your engine isn’t necessarily bad for it, it can result in something like this. For more information about whether or not it’s bad to rev your motorcycle engine, see my article here.

A running engine that is not working well is another cause of the exhaust pipes turning blue. If an engine runs low, the carburetor or fuel injector will fail and give out too much or not enough fuel.

When this happens, the combustion inside the engine heats up. This means that the exhaust pipes are heated up to a higher temperature. Some motorcycles exhaust pipes may be more susceptible to discoloration depending on the type of metal they’re made out of.

A process known as oxidation occurs when heat changes the color of metals. If the metal is heated sufficiently, it can interact with gas molecules and light waves. This color indicates how much interaction the metal had. The extreme temperatures that can pass through motorcycle exhaust pipes that a motorcycle engine isn’t normally capable of producing usually results in a blue color.

Generally you’ll see that the base of the header pipes will have the most color on them since that’s where it’s takes most of the heat. The pipe will begin to show less color the farther down you go. If most of the pipe is blue, that likely means you’ve had an engine running lean for a while that hasn’t been addressed.

How to fix blue exhaust pipes

As I had mentioned before, some people actually don’t mind the discoloration of their motorcycle exhaust pipes. Some prefer to keep the original blue color. But if you’re one who doesn’t like it, there are several ways you can get rid of that blue color.

You can replace the headers entirely as the first option. Although it’s the most expensive option, this task can be done in the privacy of your garage. I’ve changed out dozens of exhaust pipes myself on motorcycles and found that it can be easily done yourself as long as you get the right ones.

There are tons to choose from that can be used as polishes for your exhaust pipes. The pipes will discolor essentially “caked” into the pipe, so it’s important to get a metal polished specifically made for “bluing” exhaust pipes.

Blue Job (link on Amazon.com) can be an excellent option and will help remove the blue from your motorcycle’s exhaust. The product can be applied to the pipes and polished by simply rubbing it into the exhaust. The blue should be removed eventually.

If you’re open to having a new look on your motorcycle, another option you have is either painting your headers or using exhaust wrap. It may seem like a cover up, but I’ve done this on several of my motorcycle restorations and they turned out awesome.

If you’re going to paint the exhaust pipes, make sure to get a high quality paint that is high heat-tolerant so you don’t run into issues when you start the motorcycle. You can apply exhaust wrap in a matter of hours from your garage. You can read my article to learn more about the benefits and drawbacks of motorcycle exhaust wrap.

Prevention

Though having blue motorcycle pipes isn’t necessarily detrimental to the function of a motorcycle, it could be a sign of an underlying issue. If you suspect that your bike might be experiencing an issue, here are some things to watch out for.

If the blue has slowly appeared on your pipes, that’s likely a sign that it’s normal wear and tear on your motorcycle. This is especially true for very faint or barely visible blues. If this is the case, you’ll just need to polish your pipes routinely, probably once a month.

Think about how you ride if the blue color appears suddenly or quickly. Do you rev your engine often? Are you running at a high idle speed? These are two major reasons extreme heat could be leaking through your pipes. Unless you’re willing to constantly polish your pipes, decrease the amount of times you rev your motorcycle.

If your riding habits aren’t the issue, your likely culprit is that your motorcycle is running lean. If that’s the case, this is something you’ll want to promptly fix because it can cause bigger issues down the road. Another sign that your motorcycle is leaning is backfiring in the exhaust pipe and occasional lurching forward when riding.

A motorcycle running lean is usually caused by a carburetor malfunctioning because it isn’t giving the right fuel to air ratio (it usually gives too much air). Tuning your carburetor is all that’s required. This can also happen if you use aftermarket air filtering devices.

An entire video series has been created about how to restore/rebuild motorcycles. The series also includes videos on carb rebuilds and tutorials for properly installing exhaust wrap. Videos on difficult tasks like body work and electrical are also included. Click here for more information if you’re interested in restoring/building your dream motorcycle!

What about other colors?

It’s possible for metal to turn all sorts of different colors depending on what temperature you can get it at. Other than the exhaust pipes turning blue on a motorcycle, Another common color is yellow, or gold.

With a lot of headers that are discoloring, you’ll notice a mix of these two colors. The same process is responsible for yellowing exhaust pipes as blue. The yellowing of a surface is an indicator that it will eventually turn to blue if not treated properly.

Blue pipes are more difficult to polish than yellow pipes, as blue is indicative of a more mature process of oxidation. If you start noticing the yellowing discoloration of your exhaust pipes, it’s a good idea to start tackling the problem now rather than when it becomes worse and turns blue.

Similar Questions

What is the best motorcycle exhaust wrap? There are many options for exhaust wraps to be used on motorcycles, but fiberglass wrap is the most effective. It’s less expensive than other wraps and has the same quality. Click here to view the exhaust wrap that I recommend in my list for motorcycle upgrades.

How much does it cost for a motorcycle to be tuned? You can take your motorcycle to a shop to have the carburetor tuned. The average price will be between $75-$100. So if you have a four cylinder engine, the cost will range between $300 – $400.

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