When Oil Is Coming Out Of Your Motorcycle Exhaust

Your motorcycle is your pride and joy. You want to keep it for as long as you want and take it out on the road every chance you get. But sometimes, your motorcycle can always run into a problem that might need to be addressed almost immediately. So what happens when oil is coming out of your motorcycle exhaust? Should you worry? And if it’s a cause for concern, what might be triggering it?

When Oil Is Coming Out Of Your Motorcycle Exhaust
When Oil Is Coming Out Of Your Motorcycle Exhaust

Why Would Oil Leak From Your Motorcycle’s Exhaust?

If there is oil leaking from your motorcycle’s exhaust, it can stem from a wide variety of problems. It can even be a symptom to a major problem that may be developing.

Here are some things to follow and some measures to take in the event if you notice oil leaking from the exhaust  :

  • One of the more common causes for oil leakage is due to a greater proportion of oil that is recommended for gasoline blending. Because of the mismatch, excess oil would be removed from the exhaust. Depending on the model of your bike, you should consult the manual to see what the recommended blend ratio should be.
  • If the problem is not based on the mixture ratio, the oil leakage can be connected to the carburetor float. This is a tilting part that floats on gasoline. If the mixture is at a certain level, the float closes the valve that supplies the gasoline. If the float fails, it can cause oil leakage.
  • A broken crankshaft main bearing seal can also be a culprit in oil leakage. If this element deteriorates, oil can be passed on to the crankshaft and in turn, be expelled via the exhaust system.
  • A oil leakage issue can arise due to something as simple as changing the oil itself. Many bike owners overlook the task of changing the oil filter after so many oil changes. As a rule of thumb, you should change the oil filter every two oil changes. For simplicity sake, each oil filter should last you two oil changes. Once a new oil filter is install, restart the count.
  • Another cause for an oil leak can be connected to your piston rings. The more worn they are, the better chance for these rings to split. This is something that you should not ignore once you discover them. The sooner you replace them, the better off you’ll be.
  • A broken or cracked head gasket may also be the culprit. A gasket acts as a seal between the engine head and the block itself. A broken gasket can allow fluids to get past the seals and mix itself into the exhaust steam itself. In the event that oil is leaking from your exhaust, check the gasket or the engine itself for anything out of the ordinary.
  • There may also be other symptoms of failure that can cause oil to leak from the exhaust. If you have inspected all of the possible options above and still notice oil leakage, this would be a good time to find a mechanic that specializes in motorcycles to make an appropriate diagnosis.

What To Do When All Else Fails?

Depending on the model of your bike, you can take it to a mechanic that specializes in your type of motorcycle. If you have recently bought the bike, then you should be able to have a warranty in place in the event that you need replacement parts or repairs. Also, the life of your warranty will once again depend on the model of bike you may have.

Before it needs maintenance, please consult with your owner’s manual to see if there is information available for maintenance that you can do on your own. If you don’t trust yourself, then you can always rely on a professional to diagnosis the problem for you so they can make a determination on what could be the cause of the oil leak.

It’s hard to tell what may be happening in the inner workings of your motorcycle. That’s why having a professional look it over is key. If the problem can easily be fixed, you can do that yourself. For example, if the issue stems from the mixture ratio, be careful in the future. Also, if the oil filter appears to be dark and dirty, then obviously it would be time for a change. You should check your oil periodically so you know when it can be time to change it. You should use best motorcycle oil for your “wife”.

How Your Motorcycle Exhaust Works

There are two types of motorcycle exhaust pipes: the two-stroke and the four-stroke.

The two-stroke works when the piston begins to expose the exhaust port and a pulse of high-pressure gas (more specifically at levels of 80 to 100 psi) enters the pipe. It travels at about 2,700 per second. That is the equivalent to the speed of sound.

The two-stroke is considered to be an air pump. It aids in the pumping of the engine. It’s normal to assume that the crankcase in a two-stroke can pump fresh charge into the cylinder. But it’s the pipe that does the work.

In the case of a four-stroke, the pressure travels at 100 psi at full throttle. Like the two-stroke, it travels at the speed of sound down the header pipe until it reaches the junction where it meets with the other header. That’s a point of expansion. A point of expansion happens, a negative wave of pressure is bounced back up the pipe.


Oil leaking from a bike exhaust can be a cause for concern. But you won’t know for sure until you follow the tips listed above or have a mechanic take a look at it. Letting a problem like this go untreated may cause damage to your bike and may even shorten its lifespan. If you love your bike and want it to last as long as possible, you should always take the best care of it. Never let a problem go untreated when it comes to your motorcycle.

Ronald Bounds

My name is Ronald D. Bounds, founder and editor in chief here at The Rider Base. We are enthusiastic about speed and travel. This website is built to share the information for rider. We help you to choose motorcycle accessories for yourself without much time.

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