Why Do Some Motorcycle Exhaust Pipes Turn Blue?

So, it has finally happened. You've gotten your first motorcycle, and the experience has been thrilling. Nothing beats the wind in your hair, the open road ahead, and the thrum of an engine next to your leg. You're confident in your riding abilities and are constantly improving the skills you learned in preparation for owning a bike. However, on a random Tuesday afternoon, you notice your motorcycle's exhaust is turning blue. You're sure the bike didn't come like that, and you didn't paint it on. As is only natural, you're worried that something is wrong, and you start asking around your riding pack or researching why this is so. 

Well, the simple answer behind this phenomenon is heat and oxidation. If your motorcycle's exhaust is made of stainless steel, titanium, or chrome, it is likely to turn blue due to the hot gases flowing out, which, in turn, cause the metal to oxidize as it reacts with the air around it. Let's dissect this phenomenon to understand how exactly it occurs, whether it poses any danger to your motorcycle, and how it can be removed. 

To understand how exhaust bluing occurs, let's briefly go over how oxidation works. Essentially, when a molecule, atom, or even ion comes into contact with oxygen, it loses electrons, resulting in a new substance with different properties. Several metals are known to oxidize easily, meaning they can undergo oxidation with little resistance. A good example is iron, which, when oxidized, transforms into iron oxide, commonly referred to as rust. Oxidation can be either dangerous or beneficial, depending on its application. While it can render some of the most beautiful vehicles useless due to rust, it also enables combustion engines to operate, as the burning of fuel with the oxygen introduced into the combustion chamber generates the energy that powers your car. 

Regarding a motorcycle's exhaust pipe, the oxidation process is pretty much the same. The material used in the exhaust will heat up due to the hot gases flowing through it, causing a reaction with the oxygen in the air and forming a completely new layer of substance that is harmless to your motorcycle and prevents further oxidation. As such, the color can actually be beneficial, depending on how you look at it. However, some riders prefer their bike's exhaust pipe to be free of it.

One of the most common methods for removing the blue color from your bike's exhaust pipe is to polish it away using products like Autosol Metal Polish and Blue-Job Chrome Polish. The application process requires applying a specified amount of the polish to a microfiber cloth and rubbing it on the blue areas. Depending on the product, you may need to thoroughly work the paste into the pipe. A reaction will occur, reversing any bluing that may have developed on the exhaust pipe. 

The motorcycle world includes several nuances that have shaped it into what it is today. From the various types of motorcycles available to interesting facts that come in handy when you're considering your first bike, there's a seemingly endless amount of information you are expected to know. Fortunately, most bikers are often willing to help, with reliable communities online and offline ready to lend their expertise if you ever need assistance.