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How to Tell if a Dirt Bike Engine Is Blown (5 Ways)

How to Tell if a Dirt Bike Engine Is Blown (5 Ways)

If you think you’ve blown the engine on your dirt bike, there’s a few key symptoms to be aware of.

Here are 5 ways to tell if a dirt bike engine is blown:

  • The dirt bike smokes after it has already warmed up.
  • It is difficult to start.
  • The bike is constantly running low on oil.
  • The engine is unusually noisy.
  • The dirt bike’s oil looks abnormal.

There are several reasons why the engine may start to have problems. It could happen from constantly shifting gears too fast, pushing the engine to maximum power too often, pushing the engine to a high RPM while it is not moving, and many more reasons.

It is important to take care of your dirt bike so that it will last for a long time. If the dirt bike is starting to act strange, you want to get down to the bottom of it quickly. Continue reading the article to find out how to tell if a dirt bike engine is blown.

The Dirt Bike Smokes After It Has Already Warmed Up

One way to tell if a dirt bike engine is blow is if it begins to smoke after it has been running for a while. It is typical for a dirt bike to smoke just a little as soon as it is started. This happens because there is moisture in the exhaust.

After the dirt bike has had an adequate amount of time to warm up, it is not usually normal for the dirt bike engine to continue smoking. 

Fortunately, most of the time, you can easily tell what the problem may be depending on the color of the smoke that comes out if the exhaust.

  • Blue Smoke- If your start to notice blue smoke, then that usually means that oil is burning in the combustion chamber. This will typically indicate that the piston rings or valve stem seals need to be checked out.
  • White Smoke- If you see white smoke coming from your dirt bike, then that will usually mean that coolant is burning in the combustion chamber. This almost always means that there is a leaking cylinder head gasket.

If this is one of the problems you are having with your dirt bike, then the best thing to do is to check all of the parts listed above so that you can get to the root of the problem.

The Dirt Bike Is Difficult to Start

It can be a bit irritating when you are ready to take your dirt bike out and the dirt bike decides to not start so easily. This could be a sign of an engine problem and should be looked into immediately to avoid any major problems.

Here are some of the reasons why your engine is hard to start:

  • Gaskets could be leaking.
  • Valves may need to be replaced.
  • There could be a problem with the ignition.
  • The cam timing could be off.
  • There could be a problem with the fuel whether it be damage in the fueling system or you are using the wrong type of fuel.

This could be a clear sign that your engine has blown. Be sure to examine every component to find out if it is or not.

The Dirt Bike Is Constantly Running Low on Oil

Do you find yourself checking the oil in your dirt bike very regularly, and it seems to be low or completely dry every time? This could be a sign that your engine has blown. 

If you have not noticed oil leaking out of your dirt bike engine, then that means that oil is going into the combustion chamber every time it runs. This could be because the piston rings or valve seals need to be replaced.

An engine cannot run without oil. If this problem can be fixed, then you should fix it immediately.

The Dirt Bike Engine Is Unusually Noisy

Dirt bike engines make a good amount of noise in general, but the noise is a familiar, healthy-sounding noise. If you have found that you dirt bike engine has been making strange and excessive noise, then this could be a clear indicator that the engine is blown.

The noisiness can come from the top end or the bottom end of the engine. If you hear clear knocking sound from deep inside the motor, then the problem is in the bottom end of the engine. If you hear a clattering sound when the engine is started, then the problem will typically be in the top end. 

Here are some of the things that could be wrong with the top end of your engine:

  • The cam bearings need to be replaced
  • The cam chain is loose
  • The valve lash is off
  • The cam chain guide needs to be replaced

Here are some of the reasons why the bottom end of the engine is noisy:

  • There is no oil in the engine lubricating the gears, or you could be using the wrong type of oil
  • The bushing and needle bearing need to be replaced
  • The bearings are stuck or need to be replaced

There are several noises that will tell you that something is seriously wrong with your engine, such as a knocking sound, and unfortunately, it can mean pretty bad news. 

The Dirt Bike Oil Looks Abnormal

The oil that you put into your dirt bike is essential to keep the engine healthy and running smoothly. That is why it should be checked frequently and changed often. If you have been checking your oil as you should and notice something off about it, then this could be a problem for your engine.

Here are some abnormalities to look out for in your dirt bike engine oil:

  • Black Oil- When the oil has turned black, it could mean that you it is very old and should have been changed a long time ago, or it could mean that there are too many combustion byproducts going into the oil stream very often.
  • Milky Oil- Creamy oil will indicate that there is an excessive amount of moisture going into the oil system. This could happen due to a damaged water leak seal.
  • Metal in the oil- If you see tiny pieces of metal in the oil, this means that there are damaged parts within the engine. It could be a number of different parts, but it is usually very bad news.

It is best to always keep an eye on the oil for any changes in color or texture because you could easily detect major problems that are likely soon to happen. 


In conclusion, dirt bike engines should be inspected regularly in order to avoid a big disaster. If you start to have problems with your engine, it could mean that the engine is blown.

Sometimes, the engine just needs a quick repair to be back in good shape. Unfortunately, though, engines do wear out, and it could be necessary for you to replace it with a new one. Hopefully, you will get down to the bottom of your engine problems with the help of this article.

Related Reading: How to Fix A Blown 2-Stroke Engine