How to Drain Bad Gas from A Motorcycle

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Though using gas in your motorcycle is as simple as pouring some in the tank, there can be a few problems that arise if you don’t take care of the fuel properly. As crazy as it might sound, it is possible for gas to go bad and it’s important you don’t let bad gas circulate through the system.

If you suspect you have bad gas inside your motorcycle tank, it’s best to simply start over by removing it and replacing it with fresh fuel. It’s much easier to do this than it sounds.

How can you remove bad gas from your motorcycle? There are several methods to drain bad gas from motorcycles. There are several ways to drain bad gas from a motorcycle. You’ll also need to do a thorough clean of the carburetor if you have one.

I’ve owned several motorcycles that required me to drain the gas from the entire fuel system because it had been sitting for years. I’ve become very familiar with the process and can explain exactly how to do it so it won’t cause problems for you in the future.

How to drain the bad gas from your tank

It is easier to put gas in your motorcycle than to manually take it out. Because motorcycles are more accessible, it is much easier to take gas out of a bike than other vehicles.

Before going through the effort of removing the gas, you’ll need to first determine if the gas is bad. In the next section, we will discuss how to identify if gas has gone bad. Once you determine it’s bad, there are several ways of going about getting the gas out.

The petcocks are the simplest and easiest way to drain bad gas from your motorcycle tank. The hose connecting from the petcock to the carburetor should be found on the sides of the gas tank. This is how gas gets fuel to your carburetor, which then fuels the engine.

Before you engage in such an activity, make sure that your surroundings are well ventilated. You’ll also need a gas can or some other container for the gas to spill into. Turn your petcock to the right. “off” Start. The hose that is connected to your carburetor should be disconnected. You may see a little gas escaping from it.

Place the hose in your gas container so that the end is inside. Next, turn the petcock on. “on” Or “reserve” If you have it. Gravity should work it’s magic and the gas from the tank should flow through the tube and into your container.

It is possible to remove the tank completely from the bike and drain it either through the petcock holes, or through the gas cap. You will need to do more work, as you will have to remove the tank from the bike. However, this will make sure you get everything.

Next, you can use a siphon to pump. These pumps are available at most hardware shops for $10-$15. If you don’t want to mess with the petcocks or the fuel lines, this would be a good option for you.

Siphon pumps work by placing one tube end inside the gas tank through a gas cap hole, and the other in your emptying container. Place the tube inside the tank until it touches the bottom. This will ensure that you get all the gas.

Once you have started pumping the gas, the siphon pump will activate a pumping mechanism that will siphon it to the container. It is important to slow down as the gas can splatter around due to air bubbles.

If you have a carburetor, you’ll need to get the gas out of that as well. Chances are, if you’ve been running bad gas through your fuel system, there’s residual gunk left inside the carbs that could cause fuel delivery issues.

It’s possible to clean your carbs without having to remove it from your motorcycle. You can read my article on how to clean your carbs. In this case, however, I recommend that the carburetor be completely removed and cleaned. Any leftover gunk from bad gases could clog the jets.

How to Tell If the Gas is Bad

As I had mentioned before, before even thinking about needing to drain any bad gas from your motorcycle you’ll need to determine whether or not it’s bad in the first place.

There are a few simple tests you can do to ensure you’re doing the right thing for your motorcycle. Begin by observing how your motorcycle runs. Does it have trouble starting up or is it running badly? Is it unable to start? These are all possible signs your motorcycle might be running low on gas.

The smell test can be next. A smell test will reveal gas that is corroded. Bad gas usually smells stale or sour and doesn’t really smell like it’s original scent. Gas that smells bad is a sign it’s gone bad.

The gas’s appearance and color can also be inspected. Sometimes it’s hard to tell what the color is by looking inside the tank, so you may need to get a sample of it. Fresh gas should look clean and clear. If the gas has turned a darker color or has any clumps in it, that’s a sign it has gone bad.

How Long Can Gas Last in a Motorcycle Tank?

In a perfect world, gas would last forever in our motorcycles and it wouldn’t have to be yet another part of maintenance to worry about. When oil is refined, it is given a volatility property, meaning it vaporizes in a way that’s beneficial to your machine.

But this vaporizing happens whether or not you’re using your motorcycle. This means that varnish or gum deposits may eventually form. If you have unstabilized gas in your gas tank, it’s possible for it to start going bad after about 30 days. Motorcyclists usually add more gas to the tank, which will dilute the bad gases.

One prime example of varnish deposits formed in a carburetor I that was being rebuilt.

But understand that if you don’t use your motorcycle frequently, that 30 days expiration date can happen pretty quickly. Even stabilized gas can start going bad between 6 – 12 months.

So if you know you aren’t going to be using your motorcycle very often, it’s best to put in a good stabilizer in the tank and let it run through the fuel system so you don’t run into the issue of expired or spoiled gas down the road. You can read my article to learn more about the time it takes for gas in motorcycles to go bad.

What bad gas can do to your motorcycle

It’s good that you’re reading up on how to drain bad gas from your motorcycle because bad gas can have a lot of impact on it. Bad gas doesn’t necessarily ruin any parts, but it does cause a lot of frustration on your part.

Because gum and varnish deposits can build up in the gas over time, This will cause fuel system blockages. A fuel injector and a carburator have tiny holes. To ensure proper combustion in an engine, the gas must pass through these tiny holes.

These tiny holes are often blocked by a gel-like substance that sticks to the gas. Your motorcycle’s engine won’t get the fuel it needs in order to run properly or start.

Again, this doesn’t necessarily cause damage to your motorcycle, it just means you have to take time to drain the gas out of the tank and clean out the fuel delivery system.

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