White Smoke from Motorcycle Exhaust Causes and Remedies

White Smoke from Motorcycle Exhaust: Causes and Remedies

Are you seeing white smoke coming out of your exhaust pipe?

No need to panic. 

Let me assume that you don’t need to spread out a smokescreen like legendary spies outrunning enemies. So, it’s necessary to take the right steps to reduce the risks that can lead to a costly repair.

The most common colors of motorcycle smoke coming out from the exhaust are black, white, and bluish-grey smoke. Each type of smoke has different reasons behind it. 

In this article, we will talk about the causes behind white smoke from motorcycle exhaust and its solutions.

Let’s get smoked.

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What Causes White Smoke from Motorcycle Exhaust?

There can be many reasons behind that white smoke coming out of the exhaust pipe.

It’s quite common to see some white smoke coming out of the exhaust pipe of a dirt bike after a cold start. This may happen in humid conditions when there’s some overnight condensation inside the exhaust pipes. 

When you start up the bike, the exhaust system heats up and this water evaporates. It’s the vapor that comes out as white smoke. This is completely natural and only lasts for a short time. You can expect it to go away within 30 to 40 seconds.

But what if the white smoke persists for more than a few minutes?

Not so good.

This means that water or coolant is probably finding its way into the engine cylinder through a leak or a crack. 

In the worst-case scenario, that can be due to a cracked cylinder head.

motorcycle engine cylinder head

The cylinder head sits at the top of the engine block and it also contains the valve seats. They can crack or warp due to overheating. It can also happen due to uneven cooling due to air in the cooling system.

Coolant or water can leak into the engine cylinder through this crack and burn up. The residual white smoke comes out of the exhaust pipe.

Other than that, white smoke can also be due to blown or damaged engine head gaskets.

The head gaskets form a seal between the cylinder head and the engine block. This prevents the coolant from coming in contact with the fuel oil. That’s necessary for the engine to perform efficiently.

In most cases, high temperatures are the main reason behind the damage of this gasket. Once the gasket gets deformed due to heat, it can’t provide the necessary sealing.

When a gasket is damaged, coolant can leak into the engine chamber. Its combustion will generate white smoke. Depending on the degree of leakage the intensity of the smoke coming out of the pipe will vary.

Remember: this will affect the air-fuel mixture burning in the engine chamber and reduce engine performance. It can also affect the piston performance and decrease the rate of combustion. If allowed to continue, this can cause major damage to the engine.

How can you tell if the white smoke from the exhaust of the motorcycle is due to coolant burning?

Well, in some cases, the burning coolant has a distinct sweet smell.

In some old bikes, engine oil can also leak into the combustion chamber if the piston rings are damaged. But in most cases, such smoke is more bluish in nature. Chances are, it will also be accompanied by the smell of burning oil.

How to Stop Motorcycle Smoke from Exhaust?

If you feel that there’s any chance of coolant leakage in the engine, visit a repair shop immediately. Riding with a damaged cylinder head or gasket can impair your safety and the safety of others on the road.

Honestly, this isn’t the best time to get into a do-it-yourself mode. If you are not familiar with engine internals and don’t have the necessary tools, it’s best to leave things to a qualified mechanic.

The bad news is repairing a cracked cylinder head can be time-consuming. Still, it’s best to do that rather than say goodbye to your engine.

What about the costs?

It can cost you anywhere between $1400 to $2500 depending on the type of your bike and the engine design.

Holy smokes!

Now, if you think that’s expensive, imagine how much it will cost to replace the entire engine.

repairing a motorcycle engine

Let’s not forget the old adage: prevention is better than cure.

You need to get into the root cause of the blown gasket head. In case the bike is overheating, you need to find the reasons behind that.

The secret of doing that is to pay attention. (Easier said than done. I have been trying to pay attention to the right things all my life and yet here I am, talking about smoking exhausts.)

Pay close attention to the bike while riding and look out for any odd signs. Also, check the coolant level before a ride. 

Do the coolant levels drop every time without any external leakage?

Then there might be an internal leakage and you’re burning it up. You probably have major repair work ahead of you.

Keep an eye on the engine temperature if you are riding in hot conditions. If the engine temperature is rising suddenly, it might be due to a problem with the head gasket.

Trust me when I say this: overheating can cause major damage to the sensitive parts of an engine that are designed with extreme precision. Even the best quality metals will degrade when subjected to high temperatures for prolonged periods. It can also lead to motorcycle smoking from the engine.

Since a damaged cylinder head or gasket will affect the combustion efficiency of the engine, the performance will come down. That means the power output, as well as the fuel economy, will go down.

In short, white smoke from motorcycle exhaust can be an indicator that something is wrong with the motorcycle’s engine. Do NOT neglect it or hope it will pass on its own because it won’t.

Frequently Asked Questions

What does excessive white smoke from exhaust mean?

Excessive smoke that continues for minutes generally means that coolant is leaking into the engine chamber. The burning of this coolant under high heat and pressure is causing the white smoke.

Can I drive with white smoke from the exhaust?

No. The best you can do is drive to the repair shop. Driving with white smoke can damage the engine and also compromise your safety.

How do I fix white smoke from exhaust?

If the smoke is due to leakage from a cracked cylinder head or a damaged gasket, a repair is necessary. It’s best you visit an authorized technician to get it done.