Why Does My Dirt Bike Leak Gas: How to Fix It?

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Every biker’s nightmare is a leaky gas tank. Imagine you decide to go out with your dirt bike and ride it on the track and find that your motorcycle leaks gas; nothing can be more annoying.

Leaking gas is not only a waste of money; it is dangerous and pollutes the surrounding. For this reason, finding the cause and fixing the gas leak problem is essential!

A dirt bike can leak gas if you’ve over-filled the tank, the petcock is ruined, the carburetor is having issues, the gas tank has holes on it, and so on.

The question “Why does my dirt bike leak gas” is definitely a tricky one, but hey, you got lucky! Because, I’ll talk about some major causes of leaky gas tanks and how to fix them. So, stay tuned, and let’s dig in!

Reasons Behind Gas Leak In A Dirt Bike

Fuel leaks are very unsafe and dangerous. If you find traces of gas leakage or smell gasoline, you better check the bike for gas leaking thoroughly.

A dirt bike can leak gas various reasons- loose screws of the gas tank, the needle can be stuck, or the fuel switch can be damaged. I have pointed down a few reasons for the gas leak problem.

Why Does My Dirt Bike Leak Gas: How to Fix It

In the next part, I’ll be pointing out the reasons for a gas leaking dirt bike and ways to fix them:

Overfilled gas tank

A bike will leak gas when the fuel tank is overfilled. The tank definitely has space to hold a fixed quantity of gasoline. Filling gas past that limit, the tank will surely send out the extra.

How to fix it: Avoid overfilling the gas tank. Always listen to your bike and stick to the limit.

Damaged fuel petcock

The most obvious reason for leaking gas is a spoiled fuel petcock (fuel valve). It is located below the gas tank and controls the flow of the gas to the engine. This feature can quickly get damaged and leak fuel.

A fuel valve or petcock is designed to turn off the fuel supply during storage and transportation, turn it on while the bike is running, and sometimes save gas with its RES setting.

If you suspect the culprit for the leaking is the petcock, check for leakage around the valve. See gas oozing out from the bottom? There might be an issue with the fuel valve.

How to fix it: Leaky petcock can be fixed by tightening the hose clamp around the hose. If the valve does not have a gasket (gasket helps prevent leakage), putting some fuel-resistant gasket maker inside the petcock thread will help with the leaking.

If none of these works, the petcock is probably worn out or internally faulty, and you need to replace it with a new one. They are inexpensive and available in any motor shop. Before putting on the petcock, make sure the fuel tank is disconnected, and every other seal is tight.

Carburetor overflow

Another major reason for gas leaking is carburetor flooding. The carburetor is the place where fuel is mixed with air at a proper ratio that the engine needs to power the dirt bike. One reason that can cause the carburetor flood is the worn-out gasket that sits on the carburetor bowl. This bowl holds gas, and faulty or damaged gaskets can spill gas.

The carburetor fuel bowl has a drain plug, which can also be a reason for leaking gas. This plug can get loose for the vibration of the bike and eventually leak gas. Plus, if the connection between the fuel line and the carburetor gets loose, gas will surely leak from the loose hose clamp.

How to fix it: If you encounter leaky gas from the worn-out gasket on the fuel bowl, you need to replace it with a new one. If it is an issue with the drain plug, simply tighten it. That way, you can make the leakage stop!

Carburetor float valve

Every carburetor comes with a float valve that rises depending on the gas and is attached to a plunger. The plunger is the function that prohibits the excessive fuel from flowing to the bowl. You can dislocate it from the gas valve  and can cause a gas leak.

How to fix it: To fix the issue, check the plunger, then take the carburetor out and extract the float valve then clean it well; replace it if needed. Another quick solution to this problem is to tap on the carburetor bowl with a screwdriver handle and check if it helps prevent the leak. You should periodically clean your dirt bike carburetor to avoid unwanted issues.

Carburetor Drain screw

Dirt bike carburetors have a draining system of their own. Here, a drain screw is attached to the float bowl and acts like a drainage system for excess fuel. So, this feature is actually useful if you store the bike for a long time.

Gas leaks when the screws get loose, worn out, or damaged. Also, if you haven’t refueled the gas tank and the old gas is sitting there for a while, it may trigger gas leaking as well.

How to fix it: To solve the drain screw problem, you need to fix the gasket that is connecting the screws and the float bowl. You can either change the gasket or the screws to solve the “leaky” problem.

Punctured Gas tank

It is a less common cause to leak gas due to holes in the gas tank. Though we don’t want to accept the fact that dirt bikes can get more than dents, guess what, they can be “holey” too.

Holes in a gas tank can usually originate from rust or dropping too hard, or dragging across the speedway. You’ll definitely notice a lot of leaking all over places if there is a hole in the gas tank. And it will continue to leak whether the bike is on or snoozing.

To locate the exact place of leaking, you need to slightly raise the bike’s tank while it is still connected to the fuel lines. Wipe or compress air dry everything at the bottom and wait for the gas to come out to locate the felon.

How to fix it: There are no better alternatives than to replace the gas tank. If you don’t want that or running a bit low on the budget, you can always fix the hole by welding it. DO NOT strive to apply DIY, for there are chances of an explosion. If you must, take your bike to a professional for the best and safe results.

Check the fuel lines

Always check the fuel lines if none of the above is an issue for gas leaking. Check the connection from the carburetor to the fuel valve to make sure whether or not the ring is working properly.

If the fuel line is outdated, consider replacing it with a new pipe. It is better if you keep extra pipe for any kind of inconvenience.

Find the leak!

Finally, all you have to do is find the culprit and take the necessary steps to fix the faulty part, thus saving the dirt bike, saving gas wastage, and saving extra fuel money.

As this write-up focuses on the reason why would your dirt bike leak gas- I’ve tried my level best to give meaningful ideas on how to fix them.

I hope it helps you find the answers you’ve been looking for.