Frontaer is an evolving motorcycle brand. We may earn affiliate fees on some pages of this site. Read more.

Why Does My Dirt Bike Backfire On Me?

That moment when your dirt bike backfires typically sends shivers down your spine. Have you caused irreversible engine damage?

Dirt bikes backfire due to a bad air-to-fuel ratio in the combustion chamber withint the engine. This malfunction results in the loud banging sound that comes from the exhaust pipe. This typically happens when a dirt bike is starting up, though it can happen at idle or when twisting the throttle.

Short-term, there isn’t much of an issue if this happens occasionally but damage can occur to internal parts and seals if left untreated.

Dirt Bike Backfiring Issues

Any petrol-driven engine can backfire if there is too much fuel or too much air in the mixture. This can be due to excessive heat from the exhaust which ignites the fuel or even has a flame emanating from the exhaust.

Explosions are designed to happen within the engine, hence the term ‘internal combustion’ and this is based on having the correct air to fuel ratio. Each engine is different and has been designed to operate at an optimum ratio. When this ratio isn’t met, backfiring or typical.

Running Rich vs Running Lean

Have you heard the terms ‘running lean’ or ‘running rich’ before with a dirt bike? They essentially refer to the opposite ends of improper combustion, and relate more towards the fuel.

Running Rich = Too Much Fuel and Too Little Air. You’ll probably smell the petrol when you’re idling your dirt bike and the engine is likely to be running a bit rough.

Running Lean = Too Much Air and Too Little Fuel. This is where your engine is just being starved of the fuel it needs to keep combusting because the air is in excess. From here, the fuel may pass into the exhaust and later explode due to heat.

If you need to calibrate the ratios, it’s actually quite easy. You just need to use a screwdriver and locate the carburetor (often called ‘the carb’ in the dirt bike world) and turn the screws a little each time until you hear the engine running as it should.

Common Reasons Your Dirt Bike Will Backfire

Frontaer has come across numbers reasons why dirt bikes backfire. These are:

  1. Faulty Spark Plugs. You can replace these very easily and cheaply. Takes about 10 minutes actually.
  2. Bad Fuel. That fuel that you’ve left in the gas tank for 4 months has gone bad. Also, you’ll want to use 95+ because 91 and lower just isn’t what your engine was designed for.
  3. Dirty Carb. The Carburetor does the mixing of air and fuel and it may be dirty or faulty.
  4. Poor Compression. The pistons require compression within the combustion chamber to move.
  5. Air Filters Clogged. Have you cleaned out your air filters recently? This is a common reason for backfiring.
  6. The Jets are Dirty. There are several parts within the jets that need to be kept spotless and with no dirt.
  7. The Fuel Injector Is Clogged. While more rare, you may have a partial blockage in your fuel injector.

A lot of these problems you can fault-find yourself. Mechanics will charge $150+ to look over everything plus you gotta haul your dirt back to and from.

Keeping Your Dirt Bike Fresh

Routine maintenance is necessary to look after your dirt bike. After all, you don’t want to have to replace it anytime soon if it’s what you worked so hard to buy.

To stop your dirt bike from backfiring often, you’ll want to ensure your fuel injectors stay cleaned, replace your air filters often and only use premium fuels. A regular service is also recommended by a qualified mechanic.

Backfires are an indicator that something isn’t right. It’s not bad for your dirt bike for this to happen occasionally, but left untreated, it will probably send your dirt bike for an early retirement. Look after your ride and it will look after you.

Like This and Share This!

Continue Reading More Guides by Frontaer

👉 39 Most Common Dirt Bike Terms (How Many Do You Really Know?)

🔥 21 Awesome Dirt Bike Riding Tips ('Cause We Want You Safe Out There!)

🌲 How To Go Camping With Your Dirt Bike (And Arrive Home Safely)

🔧 7 Tools Every Dirt Bike Rider Must Carry (To Avoid Those Awkward Rescue Calls)

🥾 Best Dirt Bike Boots That Go The Distance (Who's Got The Best for 2021?)