Why does my dirt bike leak gas from the overflow?

Gas leaking is a basic problem for the dirt bikes. As these bikes are tough and rough, these types of problems can occur every once in a while. However, you can fix it easily by giving your bike a little time on your Sunday. So if you are also facing and doing google “Why is my dirt bike leaking gas” then you are at the right place.

Gas leaking is very annoying. When you see your fuel leaking out from your bike to the ground, you better understand that your bike is leaking gas.

Repair it as soon as possible because it can drain all our gas over the night. The gas leaking problem can occur for many
reasons. Some of the parts are very easy to fix for this gas leak problems and today I am going to talk about the gas leak in dirt bikes.

Why does a dirt bike leak gas?

Why does my dirt bike leak gas?

A dirt bike can leak gas for many reasons. Gas leaking is a very common symptom in dirt bike and it is also quite easy to repair it or you can visit your nearest garage to get it repaired. Sometimes a gas leakage can be a symptom of a bad basket or a bad seal near the Cylinder.

As I said, several causes may occur. Some of the most common causes for a dirt bike to leak gas are for a damages fuel switch, the carburetor overflow, the fuel bowl, or the carburetor drain screw. All of these parts can easily be fixed by some handy tools and no expert work required for this work or any engine work.

We have already answered many queries made by you like why does a dirt bike smoke, why sometimes it is having an issue of sputtering or bogging out.

The reason behind gas leakage

  • Damaged fuel switch
  • Carburetor overflow
  • Fuel leakage from the float bowl
  • Leakage from carburetor drain screw

How to Fix gas leakage

Today we will learn to fix leakage of a dirt bike. As I already mentioned that a dirt bike can leak gas for the 4 most common reasons. I am going to mention the name of the parts and then I will explain one by one in detail.

Damaged Fuel Switch

A bad fuel switch sometime can be the cause. Look for the fuel switch below the gas tank. You will see a switch and a pipe attached to it.
The pipe some time can be loosened enough to leak gas from it.

This switch is used for turning on and off the gas transport form It is a small part that can easily be found in online stores. I would suggest replacing the whole part. You look for the right part from here.

Carburettor overflow

Check the carburettor overflow. If the gas is leaking out of the carburettor overflow than there is might be a problem with a float valve. Check if the float valve is stuck. This valve can get stuck sometimes because of dirt.

Every carburettor has a float bowl that rises according to the gas. This float is connected to a part called a plunger. It stops the extra fuel to flow into the bowl.  Sometimes the plunger can get displaced from the float valve and it can cause the gas leak.

Check if the plunger is not placed correctly on the float valve. To fix this, take off the carburettor from your bike and remove the float bowl. Fixing this is easy.

Fuel Shutoff Valve Leaking Fuel

After removing the float bowl, clean it well or you can replace it too.  Another tip to fix it is tapping on the carb bowl with the handle of a screwdriver to see if that knocks whatever is preventing the valve from closing loose.

Fuel leakage from the float bowl

The float bowl is another reason that can cause your dirt bike to leak gas. These kinds of leaks are very slow and hard t detect. So, you have to be a little patient to check this out and fix it. Obviously, because these parts are wet and greasy and with no good sign of leaking

First, you need to get access to the screw by rotating it in place by 90 degrees. Also, there is a way to take the carburetor off from the bike to fix this issue easily.

Fuel leakage from the float bowl

Then you remove the float bowl screws and take a good look around the gasket and the body of the carburettor. The gasket is generally small with the shape of a business card.

If the gasket is old, it will look dirty and rough. You can easily replace it with a new one. You will learn to de-attach and re-attach it during the process. The good news is, carburetors rebuilt kit comes with the bike and there is always a floating bowl in it. Just take it out and
replace it with the old one.

Also, remember that the gasket carburetor has 4 screws holding the float bowl. Sometimes it simply gets loosened for some reason. Check if the gasket is new then tightened up the 4 screws to fix the problem.

Carburetor drain screw

Every carburetor of a dirt bike has a bottom part where there is a draining system. This drain system is for the overflowed fuel. However, sometimes it can cause leak gas for getting damaged. If you haven't refuel your tank for a long time then sometimes the screw part can leak gas.

The fix of this problem is to fix the gasket that is in between the screw and float bowl. Or you can buy a repair kit from the online shops. Some kit even has an extra screw for the drain nozzle. You can also replace it completely.

Leakage from carburettor drain screw

Note that some carburetor doesn’t have any screw on its drain system. If you see any large bold head in that place than you can either replace it or fix the gasket as I already mentioned above.

Additional In case everything is alright, then lastly check the fuel line from the carb to fuel valve. Check the connection and make sure that the ring is tight enough and not leaking any gas.

Sometimes the fuel line can be old and weak. Consider it by replacing the entire pipe. Because of the ethanol fix gas, these pipes don’t last long these days. So, I suggest you keep some extra pipes for this issue.


After these checking and fixing your bike will not leak any gas anymore. Check these 4 tips to fix your Gasket, fuel valve, float bowl, and pipelines and you will always ready to fix your dirt bike anywhere at any time.

I would never suggest visiting a garage to fix these simple issues. A gas leak from a dirt bike can easily be fixed by some simple practice. If you go to the garage to fix this, then they will take too much money from you which is not even worth giving. So, you better practice and
learn how to fix gas leakage.

Sources: Does your dirt bike leak gas?

Thomas A. Talley

I’m Thomas. Since childhood, I am fond of bikes and hence dirt bikes are my passion now. Ever since then, I’ve been giving advice to the beginners and this has become my hobby.

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