Why Is My Motorcycle Leaking Gas? 8 Reasons for Gas Leakage

Motorcycle gas leak is a common yet serious issue for riders. As motorcycle riders, we love the ride of thrill on highways and we do not like to stop at frequent intervals at every gas station on the way to refill the tank. Whenever we pause our adventure for a gas refill, we expect the gas to burn out completely on the ride without getting leaked for some faulty damage.

However, sometimes as riders we can smell gas when we approach our beloved motorcycle and if you have been riding a motorcycle for a very long time, just by smelling the gas you can even tell the grade of gas leaks. Although, this is not a good sign at all. An event of a gas leak from motorcycle results in reduced mileage increased fuel consumption, and gas waste in addition to being a major safety risk.

Whenever you find yourself in this kind of situation, turn off the ignition of your bike and switch off every possible fuel valve on your machine as you need to investigate the matter.

Here are a few reasons why your motorcycle leaks gas:

8 Reasons for Gas Leakage on a Motorcycle

why is my motorcycle leaking gas?
  1. Leak on the Gas Tank Filler Cap
  2. Brittle Petcock Valve Seal
  3. Worn Out Petcock Ball Valve
  4. Loose Fuel Lines
  5. Old Carburetor Housing Seal
  6. Worn Out Carburetor Float Needle
  7. Worn Out Fuel Injector Seal
  8. Build Up of Rust in the Gas Tank

Leak on the Gas Tank Filler Cap

The gas cap seal on your motorcycle could be faulty if it started leaking after you refilled the tank. This can be one of the leading causes for your motorcycle to leak gas.

Inspect the filler neck of your machine for any damage, scratch, or crack and change the cap if necessary, only if you find out that it is broken.

Also, make sure to tighten the screws of this nozzle properly at all times as even a small piece of dirt could cause a misfire in the whole system.

Brittle Petcock Valve Seal

Petrol caps are not just meant to stop fumes from entering into the internal chambers but sometimes they act as an overflow drain too. This can cause gas leaks in your motorcycle.

If your petrol cap leaks at both these places then you need to change your petcock valve assembly first before changing your petrol cap so that no other faults can occur later due to this.

Worn Out Petcock Ball Valve

The Petcock ball valve is the one that lets the engine receive fuel from your tank for combustion purposes and if it becomes loose or worn out, it will start leaking gas from its nozzle.

If you notice a gas leak on this part of your motorcycle, put a clean cloth under to catch any spills before tightening the connection between your petcock valve assembly and the hose until you stop noticing drips of gas on them.

Loose Fuel Lines

The most common reason behind fuel leakages is usually not the fuel petcock or fuel valve but the faulty hose of the fuel line which often get damaged during off-road usage or heavy traffic conditions where bumps are common threats to these lines.

Check all three hoses of your fuel line assembly carefully and tighten any loose or worn-out areas to ensure that they are stable enough to withhold the fuel pressure.

Old Carburetor Housing Seal

If you have a two-stroke motorcycle, then this is one of the most common causes of your fuel leakages.

When carburetors were introduced in these bikes for better performance, there was no other option but to use rubber seals along with them for holding the gas in their chambers properly.

Nowadays, these seals are rarely available due to old age but if you ever get one, change it before you lose all the gasoline from your tank.

Worn Out Carburetor Float Needle

Mostly found on older motorcycles that have carburetors, the fuel inlet needle is responsible for the volume of gasoline that enters your engine when you open your throttle.

Although not much can go wrong with this simple component but if it does, make sure to replace it at the earliest, or else you will end up losing gas badly within no time.

Worn Out Fuel Injector Seal

Fuel injections were introduced to motorcycles to improve their performance and substitute carburetors but if they start leaking then there is only one reason behind that – the seal becomes worn out over years of usage.

So check all the seals carefully if you have a fuel injection system in place and repair them before you run out of gasoline on your next ride.

Build Up of Rust in the Gas Tank

Rust in the Gas Tank

Although not the most common reason behind fuel leakage in motorcycles, but if your machine is a long-time resident of a humid region where rust easily takes place on its components, then you need to check for this possibility too as it may lead to gas leaking.

The buildup of rust could withdraw at the walls of your gas tank and make holes in them if left unattended. This can result in leaking gas in your motorcycle. If your motorcycle starts leaking from these holes, you will end up losing all its gasoline within no time.

So check your tank carefully for any sign of rusty patches appearing anywhere inside it along with any signs of leakage and then get rid of them immediately or else you might find yourself stranded sooner or later.

Can Gas Leakage Cause Motorcycle Shops to Close on Mondays?

Gas leakage incidents can wreak havoc on motorcycle shops, leading to unexpected closures on Mondays. The safety concerns arising from motorcycle shop monday closures are justified, as gas leakage poses significant risks. Proper inspections, maintenance, and adherence to safety protocols are crucial to prevent such incidents, ensuring the uninterrupted operation of these businesses.


With these possible reasons for motorcycles to leak gas available, you can easily identify the one responsible for your troubles by yourself as well as make sure to fix them before they start costing you more than just gas. Apart from street bikes, the same can happen to your dirt bikes too. If you want to overcome the issue of your dirt bike leaking gas, practice the aforementioned ideas.

So do not forget to check all your bike’s components carefully after every few months and then maintain them on a regular basis to prevent any events of gas leaking. It will ensure that no faulty piece of equipment spoils the show for you when it matters the most.

Happy riding!

About The Author

daniel and sarah on motorcycle

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