Motorcycle Smells Like Gas? 4 Reasons (Explained)

Riding motorcycles isn’t for the faint of heart.

You need some grit to control a powerful engine while exposed to the elements.

After enduring the wind, sun, and probably some bugs, a motorcycle smelling like gasoline is the last thing you’ll want to deal with.

In this article, we will explore why you might smell gas coming from your bike and ways you can fix it.

Here is the short answer to why motorcycles smell like gas:

It’s not normal for your motorcycle to smell like gasoline. If your motorcycle smells more potent than exhaust fumes, your bike is likely running rich or has a serious problem. Use the following checklist to find out why your bike smells like gas.

Reasons Your Bike Smells Like Gas

If your motorcycle smells like gas, there are a few things you can do to figure out what’s going on. Be aware though, a gas smell is more likely to occur on a carbureted bike than an electronic fuel injected (EFI) bike.

1. Leak from Fuel Lines & Fuel Tank

The most obvious explanation for your bike to smell like gas is a fuel leak. Fuel leaks can happen from the fuel tank itself or the lines that transport fuel from the tank into the carburetor.

Start by inspecting the fuel tank since this is where gas is stored on your bike. First, make sure you didn’t overfill your bike. Many bikes have an overflow vent that will spew out fuel from an overflow hose and onto the ground.

Another place to check for a fuel leak is the fuel valve or under the tank where the hose connections are located. Double-check that the connections are secure and start following the fuel lines. See if you can spot any areas where fuel might be dripping out.

If you do find a leak, replace the leaking piece. If you find a leak in your hose line, you’ll need to replace the entire line.

It’s ill-advised to try to “patch” a hole in your fuel line. That option should only be explored if you find yourself on the side of the road, trying to get to the nearest rest stop.

Hopefully, if your bike is leaking fuel, it’s from the connection points that can be fixed by fastening the clips. If the leak stems from the fuel valve, you can either rebuild the valve or replace it. This would depend on the options available for your model.

Please also read our article about things to check if your motorcycle has cold start problems.

2. Float Needle Stuck Open

As we mentioned in the beginning, carbureted bikes are more prone to emit a gas smell than EFI models. This is because of the float needle in the carburetor.

The float needle controls the amount of fuel that flows through the carburetor and into the engine.

Over time, gunk and debris can build up in the carburetor, which is why it’s important to clean your carbs regularly. If you don’t, the float needle can get stuck in the open position and thus allow gas to flow freely through the carb.

A stuck float needle can cause gas to leak from the carburetor or allow too much fuel into the engine. Either of these scenarios can cause the bike to smell like gas.

To make sure your float valve is not stuck in the open position without having to take the whole carb assembly apart, look at the bottom of your carb. You should see a drain hole.

If there is gas coming out of the bottom of the drain hole, you’ll need to clean your carb, as your float valve is stuck and letting too much fuel into the engine.

Make sure to also read our article about how to fix sticky handlebar grips on motorcycles.

3. Running Rich

Running rich is another reason your bike might smell like gas. This means that there is too much fuel and not enough air entering the combustion chamber in the engine. The above-mentioned float needle problem is an example of why your bike could be running rich.

There are other ways of telling if your bike is running rich, such as checking your spark plugs. If you pull your spark plugs and find that they have black tips, your bike has been running rich.

If this is the case, you’ll need to replace your spark plugs. Before doing so, tune your carburetor properly. Replacing the plugs without turning the carb will serve as a band-aid fix and you’ll find yourself repeating the process in the near future.

Also read our article about why motorcycles vibrate while braking.

4. Bad Spark Plugs

Spark plugs might tell you if your bike is running rich, but they can also be the cause of the trouble themselves.

Spark plugs ignite the fuel-air mixture from your carburetor (or fuel injectors) in the combustion chamber, thus creating power for your engine to go. When the spark plug goes bad, for whatever reason, they can no longer fire in sequence with the pistons, resulting in a misfire.

When misfiring happens in your combustion chamber, the fuel is no longer combusting and is left in the chamber. This is why you might smell fuel if your plugs are not working correctly.

Bad spark plugs can cause engine flooding and gas to leak out of your exhaust as well.

If you think your plugs have gone bad, pull them out and take a look. If they are any other color but a light, golden brown, replace them.

Be aware that this may be a temporary fix and there could be another problem with your bike that’s causing the plugs to go bad. For example, if there is a dark liquid on the tips, like oil or gas, your engine could be flooding and more extensive damage could have been done.

Replacing the spark plugs with new ones won’t fix the underlying problem. If your engine has flooded, take the bike to your local dealership for diagnostics and repairs.

Final Thoughts

If your bike smells like gas, don’t brush it off. It could be a sign of something more severe happening with the engine. Luckily, diagnosing this problem is simple and it can be fixed.

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