The exhaust pipe and the color of smoke coming out of it can tell you a lot about what might be wrong with your motorcycle. The smoke can vary in colors and range from white to gray, blue, and black.
Each of these colors shows up for a reason. In this article, we are focusing on learning more about exhaust smoke and the meaning of its colors.
What Causes Smoke in Bikes?
Whether you are riding the impressive Honda Africa Twin motorcycle or a simple scooter, you might notice excessive smoke coming out from the exhaust pipe at one point. Although that happens rarely, it is a sign that there is a mechanical issue with your bike.
Multiple reasons might be behind the motorcycle smoke, which is why its color might help you to narrow down the causes.
The colors of the smoke coming out of your bike can be:
- Blue or Gray
Regardless of the color, exhaust smoke is an indicator that your vehicle has a mechanical problem that you should solve as soon as possible. Here are more details about the potential causes depending on color.
What Does White Smoke in Bikes Mean?
The great thing about white smoke is that it can be normal and harmless for your motorcycle. If you left your bike overnight in the garage, white smoke could occur the first time you start it the next day. That’s not something to worry about because it is nothing else than water vapor.
However, water vapor should disappear after no more than 30 seconds. If you notice that white smoke is still coming out from the exhaust after that time, that might be a sign that something is wrong with the motorcycle. Additionally, if you notice a grayish shade along with the white smoke, it is another reason to visit a mechanic immediately.
The most common reason behind white smoke is burning coolant in the combustion chamber. Now, the coolant shouldn’t enter the chamber, but it might happen if there is a crack in the cylinder, or the head gasket is blown or damaged.
Those things can happen after a crash, but they can also be a consequence of normal wear and tear. Even the most durable Suzuki Motorbikes are subject to this type of damage, although they usually remain resistant for a long time.
Meaning of Black Smoke in Bikes
Unlike white smoke, black smoke is a reason to start worrying about your motorcycle immediately. If we compare all smoke signs, this one is the most troublesome. It indicates that your motorcycle is burning fuel, and that is not something that should happen.
Fuel-burning occurs because the ratio of air and fuel in your engine is unbalanced. The good news is that this might be a simple repair, which means you can take your DRZ400 on the road soon. However, in rare cases the issue might be complex.
Here is an overview of problems that might be the reason why black smoke is coming out of the exhaust pipe:
- In four-stroke units, it can be damaged or poor seating intake valve
- In two-stroke units, reeds might be cracked or broken
- The fuel injector or carb float needle is leaking
- Carb jetting is incorrect
Meaning of Blue and Gray Smoke
Unlike black smoke that indicates the motorcycle is burning fuel, smoke that comes out in blue and gray colors means that the vehicle is burning oil.
The crucial thing to mention is that it is normal for two-stroke motorcycles to let gray/blue smoke out from the exhaust pipe. The problem is that excessive smoke might indicate a power valve or spark plug not functioning properly.
The causes of oil burning will depend on whether you ride Suzuki SV650 or another bike model. However, here are some common reasons for this issue:
- PCV valve got closed somehow
- It is time to replace piston rings or cylinder walls
- Valve seals are leaking
- Damaged crankcase seal (in motorcycles that feature a clutch)
What to Do If You Face a Smoke Issue?
If you notice (excessive) smoke of any color coming out from the exhaust, stop riding right away and get to the nearest mechanic. Alternatively, you might consider finding the issue and trying to fix it yourself. Those who feel ready enough to do this should follow the instructions below.
Blue or Gray Smoke
Start by checking out spark plugs and see if there is any black soot on them. If you confirm you found some, it might be an indicator that there is an imbalance between air and fuel. But if you notice a black film that seems wet and shiny, that might be a sign of excess oil.
The next step is to inspect air cleaners. You might notice clogging, or the components might be loose. In some cases, cleaning might be enough. But if you think the issue is beyond that, it might be time to install a new part.
Finally, check the valve seals and the piston ring as you want them to be airtight. Product instructions will also include details on how to check these areas. You can also look for instructions online, but make sure to find the guide for your particular model. For example, if you own DR650, it is crucial to find a product manual for that motorcycle.
As we mentioned, your engine might need to let out white smoke until it warms up, and that is perfectly normal. That is especially true if you are in cold climates, or the temperature is below 50F.
However, if white smoke continues after 30-40 seconds, check if the water is somehow entering the engine. Additionally, inspect the oil reservoir and see if there is too much oil there. Finally, look for issues in pistons, seals, and cylinder heads.
Why Is It Best to Seek Professional Assistance?
You might not be experienced in fixing motorcycle issues, or you might make a mistake in identifying the problem. That is why the best move is to take the bike to a local mechanic that you can trust. Their knowledge and experience are a guarantee that they will fix the issue for you and get you back on the road quickly!