Why Is My Motorcycle Losing Power When Accelerating?

Biker girl in a leather jacket on a motorcycle

One of the most exhilarating experiences of riding experiences is accelerating on your motorcycle. It is not just fun, but one of the most vital aspects of riding. Basically, you wouldn’t be able to move anywhere without it.

Accelerating problems with your motorcycle can be extremely frustrating. There are times when you give it gas, but it does just the opposite, loses it. If this is happening, there are a few possible reasons why.

Probable Reasons Your Motorcycle Is Losing Power While Accelerating

Vacuum Leak On Intake Boot or Carburetor

Vacuum leaks are very common on motorcycles, especially older ones. A vacuum leak happens when there is a crack in the intake boot or the carburetor, which supplies air to your engine. When you accelerate, the pressure builds up and the crack gets larger. This causes a loss of power because not as much air is reaching your engine as it should be.

To fix this problem, you can replace your torn or cracked rubber boots with new ones. Carrying spare boots with you at all times is highly recommended if you know there’s a chance of getting stranded somewhere without one. Also, try tightening any loose screws around the carburetor before replacing anything since most cracks happen near these areas due to vibrations while riding.

Damaged Carburetor Spring

A carburetor spring might be bent or damaged and not supply enough pressure to the other components. This means that your throttle cable, which should pull the throttle open, can’t do its job. It will cause a decrease in power as your engine won’t get all of the air it needs.

When the spring is open, it might not be able to open the butterfly valve all the way, which is what controls how much air your engine receives. If you can’t fix it on your own, consider taking it to a shop and they should be able to repair or replace it for you.

Clogged Air Filter

If your air filter is clogged with dirt and debris because you haven’t been changing the oil regularly, then there’s going to be one outcome: poor acceleration. The engine needs clean air to run smoothly and efficiently, so if yours isn’t getting it, you’re losing horsepower too.

Dirty oil can also cause clogging and deterioration of parts like pistons and valves. This makes them weaker and less powerful than they should be.

Low-Quality Fuel

If you’ve been using low-quality gasoline, then it can cause your fuel system to malfunction. You need high-quality gas because it will create just the right amount of combustion for better acceleration.

This led to your motorcycle losing power while accelerating because the fuel wasn’t able to provide the power needed to accelerate at a faster rate. Using low-quality fuel can also cause your engine to run hotter and damage its components, which ultimately causes it to lose power as well.

Worn Out Spark Plugs

Worn-out spark plugs are also known to affect your motorcycle’s power performance while accelerating. When the metal center electrode erodes or corrodes completely, so does its ability to transfer electricity properly. Replacing them is usually cheaper than repairing extensive engine damage caused by running with bad spark plugs in place.

If one of these reasons is causing poor acceleration on your motorcycle, take some time to investigate and diagnose the problem before taking further action.

Carburetor Spring is Situated Backwards

Most carburetor springs are situated backward or bent in some way when you get your motorcycle. It usually happens after a fall when the throttle cable is pulled back towards the engine, bending or breaking it in the process.

If you’ve lost power while accelerating because of this reason, you’ll need to replace your broken spring with a new one. Besides that, try tightening any screws on your carburetor before buying anything since most cracks happen near these areas due to vibrations while riding.

Additional Slack in the Throttle Cable

If your throttle cable has too much slack in it, then it will not be able to pull the throttle open all the way. This means that your engine won’t get as much air as it needs to run smoothly because there’s no tension on the cable.

It can also affect your motorcycle’s acceleration performance because if you don’t have enough pressure trying to push the throttle open fast enough, then it takes longer for that process to happen and this causes a loss of power. You might even unintentionally shut off your motorcycle when trying to accelerate quickly. First, tighten any screws around the carburetor before replacing anything since most cracks happen near these areas due to vibrations while riding.


If you’ve been facing any of the above-mentioned issues, then your motorcycle might be losing power while accelerating and it is time you consider fixing it. Find out the exact problem and try to fix it yourself before taking it to a shop for repairs or replacement. You can follow these tips to ensure that your throttle cable won’t cause problems again in the future.

Thank you for reading!

About The Author

daniel and sarah on motorcycle

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