How to Fix Motorcycle Backfire

How do I stop my motorcycle exhaust from popping?

A backfire describes the loud pop or bang you hear in your motorcycle’s exhaust when it’s not tuned quite right.

There are a number of different reasons why your motorcycle backfires, some easier to fix than others.

Backfire is caused by a secondary, unexpected combustion when there is unburnt fuel in the exhaust.

The underlying cause of motorcycle backfires is an improper fuel mixture.

What is the cause of Motorcycle Backfire?

The improper fuel mixture that causes the backfire can be attributed to a number of things. The most common ones to check are:

• Loose exhaust pipes or carb manifolds.
• Improper exhaust system for the current jetting.
• Weak spark.
• Improper ignition timing.
• Too much fuel.
• Too much air.
• Dirty carbs or clogged jets.

Motorcycle Backfire on Acceleration

If your motorcycle backfires when your speed up, the likely culprits include:

• The intake circuit.
• Ignition timing.
• Carbs out of sync.
• Improper valve clearance.

When you accelerate and twist the throttle, you introduce more air to the air fuel mixture, if there is a leak or timing is off, the mixture will be incorrect and a backfire can happen.

If your motorcycle is backfiring on acceleration, start with the items above.

Motorcycle Backfire on Deceleration

The most common causes for backfiring as you slow down and close the throttle, include:

• Aftermarket or open exhausts without carb jetting.
• Carbs out of sync.
• Low compression.

Any of these situations can cause excess fuel left in the exhaust, which eventually heats up, ignites, and “pops.”

How do you fix backfire on a motorcycle?

Start with the easy fixes first and move down the list:

• Make sure everything is properly tightened.
• Did you change the air filter or air box without rejetting the carbs?
• Did you change the exhaust system without rejetting the carbs.
• Is your battery charged and healthy?
• Is your timing correct?
• Are your carbs clean and tuned properly?

Backfire can be prevented and a properly tuned engine can be maintained with regular maintenance and inspection.

If you get a backfire every once in a while, it’s probably not much to worry about.

However, if your motorcycle is constantly backfiring, you’ll want to identify and fix the cause of the issue.

Is backfire bad for a motorcycle?

Motorcycle backfire is the result of an improperly tuned engine and fuel system.

Left unfixed, backfire can be bad for your motorcycle.

The most common issues caused by backfire include:

• Overheating of the engine.
• Overheating of the exhaust.
• Poor mileage.
• Loss of power.