Decreasing oil levels over time or blue smoke when riding are both signs of your ATV burning oil. This does not, however, necessarily equal total disaster. But we care for our machines and tend to assume the worst when things like this happen.
Knowing more about what’s causing your ATV to burn oil will help you sleep better at night and may help you determine whether you need to address the cause.
The most common cause to why an ATV burn oil is worn or damaged piston rings or worn engine due to dirt bypassing the air filter. But it can also be caused by simply using the wrong type of oil for the specific bike. A leak-down test will, in most cases, tell you if there is an issue with the engine, causing it to burn oil.
What does it actually mean when an ATV is “burning oil”?
The term of a vehicle “burning oil” refers to when oil for some reason enters the air/fuel mixture and gets set on fire in the combustion chamber by the spark plug.
This contamination of the fuel disrupts the combustion process and may cause the bike not to perform as it should. It is also what’s causing blueish smoke to come out of the ATVs exhaust system.
In some cases, people refer to their vehicle burning oil just because they have noticed a decrease in the engine’s oil. However, it may be other reasons actually causing the levels to drop.
More on the most common, and some of the less common reasons why an ATV will burn oil
Let’s have a closer look at the most common reasons and some less common reasons why an ATV would be burning oil.
You may be surprised that some of them are not as disastrous as you may have feared.
The wrong type of oil
Sticking to the type of oil recommended by the manufacturer recommends is usually a good idea. Using a different type, or in some cases, even just using a different brand will void your warranty.
If you use mineral oil instead of synthetic oil, or if you use a different viscosity grade (thickness) than recommended, this may be what’s causing your quad to burn oil.
Strange as it might seem, even using a different brand than what’s recommended may, in some cases, cause your bike to burn oil. Switching back to the one recommended by the manufacturer may be just what it needs.
But whatever you do, do not mix synthetic and mineral oil. If you are not sure what oil is on the bike, you need to replace it not to cause any additional engine issues.
If you bought the bike used, changing the oil is the first thing to try if it burns oil. You never know what type the previous owner put into it.
It is not wasted time or money regardless, as one extra oil change will only do good for your ATV.
Seized, worn, or damaged piston rings
A big part of the piston ring’s job is to keep oil from the crankcase from entering the air/fuel mixture in the combustion chamber.
If something prevents them from functioning properly, oil may leak past the rings, and the ATV may start burning engine oil together with the gas.
Over time the rings can wear down, making a bad seal against the cylinder walls. Sometimes, pieces of the rings may break loose to be blown out through the exhaust system.
A quick compression test should be able to tell you if the rings are ok. If you notice a puddle of oil in the bottom of the air filter housing, this would also be a strong indicator of bad piston rings.
If the bike has been sitting for some time, or if you only use it for some minutes each time without letting it heat up properly, the rings may seize up. This will also create a bad seal, with possible oil burning as a result.
In this case, going for a good, long ride to warm things up may be all that it takes for the rings to come loose and consequently fix your oil burning issue.
Worn cylinder, valve stem seals, and valve guides
Any engine will wear over time. Not breaking in the bike properly or letting dirt get past a damaged or badly sealed air filter may speed up this process significantly.
As the engine wears, seals that need to be tight may start leaking. This way, oil can get places it is not supposed to be, like inside the bike’s combustion chamber. Here the oil will burn together with the fuel/air mixture.
To ensure optimum longevity, always follow the manufacturer’s break-in procedure when the bike is new.
And make it a habit to make sure the air filter cover is fitted properly at all times and that no fastening clips are missing on the air filter cover.
Not enough oil
Yup, too little oil may actually be the cause of your bike burning oil.
The bike depends on oil for lubrication and cooling. When there is not enough oil in the engine, friction between the different engine components increase.
This will, in turn, create more heat, sometimes enough to burn the oil that’s already there. The hotter the engine gets, the more oil it will burn.
To stop this vicious cycle, you can start by simply adding the correct amount of oil.
Not really burning any oil after all
The rookie mistake of not checking the oil levels correctly, resulting in an inaccurate reading, is way more common than you may think.
When you check the oil levels, using the dipstick, the bike must sit on as level ground as possible. If it tilts a bit back or to the right when you check one day but then tilts a bit to the left or the front when you check the next day, you will not get the same reading.
Ensure you compare apples with apples by doing accurate readings over time to be completely sure oil levels are actually decreasing.
How to tell if the bike is burning oil
Blue or bluish smoke coming out of the bike’s exhaust is usually a clear indicator of your ATV burning oil.
In this article, I dive a bit deeper into why blue smoke appears, plus how to troubleshoot and repair what’s causing it.
It’s worth noticing that blue smoke from a two-stroke is, in most cases, perfectly normal. When starting a cold two-stroke engine, left-over fuel and oil from the last time the engine run will make the bike run a bit rich in the beginning.
This will create blue smoke.
But if the bike keeps smoking a lot when it’s warm, you should consider digging a bit deeper into what’s causing it. I would recommend you begin by having a look at the jetting.
Blue smoke on four-stroke bikes, on the other hand, is not a good sign.
Oil being burned will create a distinct smell. Some, myself included, love the smell of burning two-stroke oil. Probably because it usually means I’m having fun. Others can’t stand it.
But if your four-stroke starts smelling similar to your lawnmower or chainsaw, the alarm bells should start ringing.
Oil-levels decreasing over time
If your oil levels decrease slowly over time, it may be a sign of your bike burning oil, but it may also be caused by a small leak somewhere.
Find a dry spot, like a clean garage floor, to park your bike after you are done riding. If there is an oil leak, you should notice a spot of oil underneath it after some time.
If the leak is tiny, it may not even drip down on the ground. Check the underside of the engine to see if you notice any oil sweating out. You may need to take off any skid plates for better access to the engine.
Often you may see a drop slightly hanging down, but just not enough of a leak for the drops to fall on the ground. Also, inspect the area around the oil filter.
Not replacing or not properly firing the seal between the engine and the oil filter is a common cause for small oil leaks.
If you find any leaks, this needs to be addressed to see if this fixes your issue with decreasing oil levels.
Can burning oil hurt the bike?
The answer to this question is both yes and no.
The actual process of oil-burning on its own does not damage the bike. But if oil levels drop below minimum levels, you may risk damaging the bike due to running it dry.
When there is not enough oil, the engine parts will not get the lubrication and cooling they need, potentially ruining the engine.
Depending on what’s causing the oil burning, it may be a sign of serious engine damage. In other cases, the issue can be easily fixed with no risk of further damage.