Why Is My ATV Smoking? How To Fix It Guide


There are few hobbies quite as fun as racing through a trail on an ATV, but that can go awry in no time as your ATV starts to smoke. What does this mean for your quad? Is it irreparable or an easy fix?

ATVs naturally emit some amount of white smoke as condensation and black smoke as exhaust, but excessive smoke or smoke of other colors can mean you have a problem on your hands. Blue smoke can be normal in some engines in small amounts, but too much is cause for concern.

It can be tricky to tell the difference between specific problems. In this article, we will look at some of the symptoms and causes of ATVs smoking, as well as some rudimentary tests you can do to check the health of your engine.

What Does White Smoke Mean?

Generally, white smoke is the most innocuous color of smoke you can hope to see coming from your ATV’s engine. In some special circumstances, though, it could turn out to be a severe issue requiring a lot of work to fix.

Most ATVs emit white smoke when you first start the engine, and it usually stops within a few minutes. This is because of water evaporating and is of no concern when first starting your engine.

The timing of white smoke is everything, though, because if your ATV starts putting out clouds of white smoke when the engine is up to operating temperature, it means that you likely have coolant or water in your combustion chamber.

How do you diagnose the exact issue in that case? Start by checking your coolant levels in your radiator to determine if you have a leak. If you do indeed have a leak, you’ll notice low coolant levels and a sickly sweet smell from your radiator.

This could be the result of various issues, including a damaged radiator, hose, busted head gasket, or water pump. No matter the exact problem, you definitely don’t want to be riding until it’s fixed.

If you get lots of white smoke while riding your quad, immediately stop riding and try to figure out your problem so you can fix it.

If you continue to ride your ATV while it has a coolant problem, you run the risk of overheating, and you most definitely don’t want that. The quicker you fix your problem, the faster you can get back to the trails.

This video helps explain the different colors of smoke and what they might mean:

What To Check When You Have White Smoke

There could be several reasons your quad is blowing white smoke, so be prepared to do some basic checks.

  • Check intake gaskets. Bad gaskets can cause coolant to leak into the cylinders and combust, causing white smoke from your exhaust.
  • Check the head gasket on your cylinder head. If the gasket gets damaged or destroyed, your cylinder head can overheat and potentially crack.

It is extremely important to make sure your cylinder head and engine block are not cracked – even the tiniest cracks will spread and effectively destroy your engine, and you definitely don’t want that to happen while you’re riding.

It’s best to replace the cylinder head if there are any signs of cracking.

Another dire situation to look for white smoke is any time after your ATV has been submerged. Any time that your ATV is underwater, it can get water into your cylinders that will combust if you try to start or run your bike without totally cleaning your ATV out.

We’ll discuss the specific procedure for a submerged ATV later, but keep in mind to never try to start a submerged quad!

Replacing Melted Gaskets

The importance of gaskets in your engine cannot be overstated, as they are what keeps operating fluids in sealed components of the engine. If you need to replace a gasket like your intake or head gaskets, the old one will probably be baked or melted onto wherever you’re leaking from.

Gaskets can be made of rubber, steel, or a combination of the two. Regardless of the type, gaskets will end up melted after some time. Naturally, this causes a lot of problems when putting a new one on.

Several methods of removing baked-on gaskets are:

  • Razors or scraping tools
  • Scotch Brite scrub pads are great all-purpose tools for cleaning, and this situation is no exception.
  • Contact cleaner will help loosen stubborn gasket pieces to be scrubbed or scraped off.

Here’s a video of a Honda blowing white smoke and what the guy did to fix it:

Troubleshooting ATV Black Smoke

If your ATV is emitting black smoke from your exhaust, it’s probably not a huge problem to worry about. There can be numerous reasons for black smoke, though, and some are more serious and costly to fix than others.

Some reasons for black smoke include, but are not limited to:

  • Not enough air intake in your engine
  • Too much air in your engine
  • Defective carburetor
  • Defective fuel injector
  • Defective controller
  • Not using the correct type of fuel
  • Engine overheating

As you can see, the cause of black smoke can range from benign to fairly serious. In general, black smoke means that you have a rich fuel-air mixture in your engine, which means you either have too much air or too much fuel in the mix.

If the problem primarily occurs when you start the ATV but lightens up when you get going, it may be a minor tweak not worth worrying about.

It may be worth your while to check your carburetor to ensure that it is set to the optimal setting for your fuel-air mixture. If you have a digital carburetor, that needs to be checked as well.

If it isn’t working correctly, you may be facing a replacement. If you aren’t a mechanic, there’s no shame in taking your ATV to one, so you can be sure that your quad is getting the best possible care.

Checking and Cleaning Your Air Filter

If this is the case, you want to first start by checking your air filter. If it’s dirty, you may have found your culprit. A dirty air filter clogged by dirt and other particulates doesn’t allow the correct amount of air as determined by your carburetor.

It’s very common for ATV owners not to check the cleanliness of their air filters regularly, and it can be clogged up very easily. Ideally, you want to check your filter before each ride. This also causes loss or reduction of power.

Also, keep in mind that the frequency you should be changing your air filter is heavily dependent on the type of environment you ride in. Dirt, insects, plant, and tree debris all can easily get stuck in your filter and cause your ATV to slow and spew black smoke.

If you’re riding in a lot of creeks, rivers, or mud, you’ll want to check this more than if you’re just going down a typical trail or around the yard.

Cleaning your filter should be a pretty simple affair and only differs a little bit depending on the type of filter you have. A paper filter can be easily beat against your hand to release debris and particulates.

A foam filter requires a little more work, but a little soap and water should do the trick and get it clean again.

We made a dedicated How To Clean an ATV Air Filter article you can check out for more.

First, start by getting the large debris off, then massage the finer stuff out. Let the filter air dry, and make sure to lubricate both the filter and airbox of your quad before replacing it.

When cleaning your filter, always be sure to be observant for any signs of wear and tear – if it looks worn or severely dirty, it may just be easier to invest in a new one. You can’t be too careful with the health of your ATV.

Other causes of black smoke are generally easy to diagnose and don’t require a lot of special equipment.

Some things to check are:

  • Check to make sure your running engine cylinders aren’t different temperatures. If they are, this means you have a clogged or faulty fuel injector.
  • Check with a feeler gauge to make sure the clearance of your valves is standard. If you’re seeing black smoke and hearing a knocking sound, this may be your problem. Fixing this problem requires some tools and know-how, so do your research or go to a trusted mechanic.

Occasionally when your engine block is overheating, it can cause black smoke. Always be sure to look out for blue smoke, which is a more normal sign of overheating.

If a problem (generally with the radiator) causing the engine block to overheat isn’t taken care of soon, it can effectively wreck your whole engine.

While you should always do a thorough check to make sure black smoke isn’t a cause for serious concern, most of the time, it just means you’re running too rich.

If you ever have cause for concern beyond that, take your ATV to a trusted professional immediately.

What To Do About Blue Smoke

While black smoke is just an unbalanced air-fuel mixture, blue smoke is generally because of oil burning and escaping out of your exhaust.

This is a troublesome issue that causes you to burn through a lot of oil – the faster you keep running out, the worse a problem you have with your oil.

As a side note, 2-stroke quads often emit blue or grey smoke. 4-stroke engines are where blue smoke is problematic.

Your engine has valves that open into the cylinders, where fuel is combusted to power your ATV. There are seals to ensure that oil can’t get in there, but sometimes those seals become worn, cracked, or just plain broken.

When that happens, oil leaks into the cylinders where it’s burned along with your air-fuel mixture, and blue smoke comes out of your exhaust.

This can be difficult to fix at home, so unless you’re confident in your abilities, it may be best to go to a mechanic.

Another cause of burning oil can be the oil itself. Poor quality oil has a greater tendency to leak, even when your seals are in good shape. In addition, you should always add a fuel treatment to your gas – the treatment will run through your entire engine and help keep it clean!

There’s another source of burning oil as well, and that’s problems with your piston rings and/or spark plugs. If your spark plugs turn out to be bad, always make sure to check your piston rings too before putting in a new plug – it’ll just get ruined if the rings are bad too.

This is a fairly complex and pricey procedure to fix, but be certain to use good, clean oil if you do because old oil will cause additional friction that will wear your piston rings out much faster.

The Importance of Maintenance

Many people see ATVs as oversized toys, but don’t be fooled – they require at least as much upkeep as a car, perhaps more so because of the conditions they are often rode in. If you keep up with the care that your quad needs, you can keep riding the trails for a very long time.

In this section, we’ll discuss some important routine maintenance that will help maximize your ATV lifetime.

Check Your Fluids

When oil levels get low, there are all kinds of particulates that get into your oil. These particles can build up over time, especially if you don’t regularly check and change your oil. If continually neglected, these particles get into your engine and begin causing all kinds of damage.

Check Your Filters

We talked about the importance of your air filter on your engine, but your oil filter is equally important to keep up with. Without a clean, functional oil filter, your oil will degrade much faster and even become detrimental to the engine.

Ideally, you want to be checking your filters before every ride to make sure they’re in tip-top shape.

Keep Your Radiator Happy

Your radiator is what keeps your engine from overheating, so you want to pay special attention to it. If you neglect to check your coolant levels before every ride, you may find you have a bad leak that causes you to overheat in the middle of a ride!

To prevent this, you want to use high-quality coolant and check the level often. If you do this, you’ll never have to worry about overheating again. This will also keep the chances of white smoke from the coolant in the engine to a minimum!

Break It in Slowly

It can be exciting to start your ATV and immediately want to ride hard but resist the urge. When starting a new ATV or your current one, it’s best to start slowly.

Start the throttle slowly and ramp up the engine over time after starting it. This will reduce the stress on your engine as it acclimates to running conditions, keeping it in top form for the ride ahead.

Keep It Clean

Everyone wants to keep their valuable items clean, and your ATV is no exception. If anything, it’s functionally important to clean your ATV regularly.

You want to clean the top, sides, and especially the undercarriage of your ATV, being sure to focus on any debris that appears to be caked on. This kind of debris can cause wear and tear over time, especially if it’s wet. Nobody wants a rusty engine, so keep it clean!

Keep It Tight

Nuts, bolts, and hubs can all become loose over time, and it’s extremely important to note if any are feeling loose. Immediately tighten any loose nuts, bolts, or hubs you come across, or else you shouldn’t ride until you are able.

It can be very dangerous to ride with any loose components on your ATV and can cause further damage that might not be so minor as a loose bolt. We don’t want any wheels falling off, do we?

Your ATV Is Not a Submarine

I know, I know – your ATV is your dedicated outdoor recreational vehicle, so it should be able to handle some water. While your quad can indeed handle going through creeks and the like, you don’t ever want to fully submerge your ATV. If you do, you’ll find yourself in a very sticky situation!

Follow these steps to save your waterlogged quad:

  1. Remove your ATV from the water or mud.
  2. Drain and remove your air filter and air box. Let air dry.
  3. Get your bike vertical to drain out any lingering water.
  4. Drain your carburetor and gas tanks.
  5. Flush coolant system completely.
  6. Drain remaining water in your cylinders.
  7. Replace spark plugs.
  8. Change the oil.
  9. Flush your brakes.

Final Thoughts

While ATVs are some of the most fun outdoor equipment you can own, they come with a responsibility similar to a car or truck. If you treat your ATV with love and care, it will continue to run for a long time.

On the other hand, if you run your ATV ragged, it can present any number of problems – from black, blue, or white smoke to much worse problems.

Rob

That's me sinking another ATV. I love to ride no matter what it is, snowmobiles, four wheelers, dirt bikes, and anything else off-roading. I've experienced my fair share of machines, and like to share that experience here.

Recent Posts