Have you ever noticed smoke or a burning smell coming from your ATV and wondered what’s going on? It’s a sight that can raise alarms, but understanding the nuances of these smoky signals can be incredibly helpful. The color of the smoke, its origin, and how it started can offer important clues about your ATV’s health and what steps you should take next.
In this post, we go into the various colors of smoke—be it white, blue, gray, black, or even the presence of a burning smell—and unravel their meanings. For instance, the fleeting white smoke on a cold start might be nothing to worry about, but persistent blue smoke could signal a more serious issue. Each color and type of smoke or smell holds a key to understanding and resolving problems with your ATV.
Join us as we break down these smoke signals in detail, helping you to diagnose and address the problems you’re having.
Below, I go over the colors and all the reasons for the smoke.
- Cold start – When starting your engine, it’s not uncommon to see some smoke come out the tailpipe as the hot air meets the cool air. You may even see some moisture. If you see smoke for a brief time when you’re first starting, then it’s not a concern.
- 2-stroke – If you have a 2-stroke, then it burns oil and seeing some smoke coming from the exhaust is normal. You may even have a huge plum of white smoke if the carbureted machine has been sitting for a while. This is normal for a 2-stroke, especially when starting it, to see white or often blueish gray smoke come out the pipe.
- Water In Cylinders – If you got water in your engine cylinders, then seeing white smoke would be expected.
- Coolant leak – If the coolant is getting into the combustion chamber, it can result in white smoke from the exhaust. A blown head gasket or a cracked head or cylinder is often the culprit.
- Burning Oil – Just like with 2-stroke that burns oil, if your 4-stroke is burning oil then white smoke can be seen. This could be due to worn valve seals, piston rings, or other internal engine issues.
2. Blue / Gray:
- Too Much Oil – If too much oil has been added to the engine, it can result in blue smoke. Always ensure you’re filling to the correct level.
- Burning Oil: This usually indicates that oil is being burned in the combustion chamber. Potential causes include worn piston rings, valve seals, or a malfunctioning PCV valve.
- 2-stroke – Blue or gray smoke is more common on 2-stroke as they burn the oil. The color can be white, blue, or gray, but smoke at the start of turning the 2-stroke on is common, especially if it’s been sitting.
If you’re seeing blue or gray smoke, and you don’t have a 2-stroke, then something seriously wrong. The dealership or local repair shop is needed if you don’t know what you’re doing.
- Rich Air/Fuel Mixture: Black smoke usually indicates an overly rich air/fuel mixture. This means there’s too much fuel and not enough air entering the cylinder for combustion. It could be due to a faulty injector, a clogged air filter, bad sensors, clogged carburetor and more. I suggest replacing your spark plugs first if you’re getting black smoke.
- Dirty Air Filter: A clogged or dirty air filter can restrict the amount of air going into the combustion chamber, causing an imbalanced air/fuel mixture. I’ve even seen dirt daubers, mice, and mud make its way to the intake and restrict airflow. Take the air filter out and see what is blocking when you have black smoke.
4. Burning Smell
If it smells like your machine is burning, has a rubber burning smell or similar, then check out my guide here on how to fix it.
5. Electrical Burning
Electrical fires have their own unique smell and color to them. Electrical smoke and fires often smell like burning rubber as the wires melt.
You can also see blue or white smoke coming from electrical fires, and it must be put out quickly or the whole thing will burn.
Electrical fires are more likely to happen near parts of the machine that consume a lot of power, like the starter, winch, relay and similar areas. Pay close attention to these areas if you smell or see smoke to see if it’s an electrical fire. It’s often a short somewhere, and it can be accompanied by a check engine light or the engine not running right.
Sometimes it’s as simple as being too dirty and that is why it’s starting to smoke.
I see guys with mud on their radiators and damaged radiator hoses complain of smoke, but all they need to do is either clean the thing from mud or fix the hoses.
The Biggest Reason For The Smoke
The biggest reasons for a smoke blowing ATV is often from the lack of maintenance or not driving them enough.
Oil, spark plugs and other major parts wear out and when they do, it causes all kinds of running issues. You need to do routine maintenance to keep it in good running condition.
You also need to drive often or perform long-term storage on it if you’re not riding for a few months or more. It’s common for an ATV, that’s been sitting for a long time, to smoke due to the condensation that builds up in the pipe, gas going bad, and the oil and parts wearing out from inactivity.
Avoid Submerging Your ATV
With so many people mudding and completely putting them in the mud, it’s more common to see smoke.
A hot engine touching cool water will create smoke and steam. This water can find its way into places and stay there until it’s broken free later, and then you see smoke as it hits the hot engine.
If you’re mudding a lot, you can expect to see more smoke, but you still need to keep an eye out. If you can, avoid completely putting your ATV in water or mud.
Understanding the reasons behind a smoking ATV is important in keeping it going for a long time.
As talked about, the color and nature of the smoke and where it’s coming from, can provide valuable diagnostic cues. Whether it’s the common white smoke of a cold start or the more concerning blue smoke indicating burning oil, being proactive in addressing these signals is key.
Remember, routine maintenance, staying on top of changes, and addressing issues head-on will not only reduce the chances of it smoking but also prolong its life.