A motorcycle can sputter and backfire due to vacuum issues, carburetor issues, clogged carburetor, bad ignition timing, bad spark plug wire, bad spark plugs, fuel leak, or tuning issues.
A motorcycle will backfire on de-acceleration due to ignition timing being messed up, bad spark plugs, or other ignition problems.
The backfire on the motorcycle when you de-accelerate is caused by the unburnt fuel left in the combustion chamber that suddenly ignites and creates the backfire.
You can increase motorcycles RPM and the power and torque by upjetting the carb or ECU retuning.
To increase peak RPM, I would suggest going for better pistons, connecting rods and crank.
Preferable to have a new stronger block and then let your carb and ECU flow the fuel freely into it.
To adjust the air fuel mixture on a motorcycle carburetor find the air fuel mixture screws which can be in different locations on the carburetor depending on the motorcycle.
Verify the motorcycle carburetor is set to stock settings:
Start the motorcycle and bring to operating temperature.
Set idle speed adjusting screw, clockwise to increase rpm, counter-clockwise to decrease rpm.
Adjust idle mixture by turning idle mixture screw slowly clockwise until the engine runs poorly.
Then turn the idle mixture screw counterclockwise slowly until it runs properly again.
If your motorcycle is losing power when accelerating you could have a bad spark plug, bad ignition coil, clogged fuel filter, clogged fuel line, clogged air filter.
A motorcycle can bog down when you give it gas due to a clogged carburetor, dirty carburetor, clogged main jet in the carburetor, dirty air filter, clogged fuel line, etc.
Most often when your motorcycle engine bogs down when you give it gas and lay on the throttle it means the engine is not getting enough fuel to the carburetor and engine.
The carburetor may need cleaning or the fuel filter may be clogged or the fuel line is clogged.
The cost to tune a motorcycle carburetor ranges from $100.00 to as much as $200.00
Tuning the carburetor yourself can be done and cheaper if you know what you're doing or can learn but hiring a professional to tune the motorcycle carburetor is worth it to get the proper results.
No matter how often you ride you should give your bike a tune-up at least once a year.
Motorcycle exhaust popping is bad as it's an indication of either a timing issue or bad spark plug or the carburetor being out of adjustment and allowing too much fuel to enter the combustion chamber.
Popping on deceleration is due to unburnt fuel being ignited in the exhaust.
The reason you do not hear this on a bike with a stock exhaust is due to the baffling of the stock exhaust.
It is not only much quieter but also does not allow the fresh air to enter the exhaust due to reversion.
A motorcycle will shoot flames out the exhaust when the engine ignition timing is off and the fuel is not burning properly.
Either your motorcycle is getting too much fuel or the timing is off on the engine causing the engine to not burn the fuel correctly which leaves unburnt fuel in the combustion chamber of the engine.
Motorcycle backfire is something that happens when a motorcycle engine gets too much fuel or air.
Bikes or motorcycles come setup so that the carburetor (or fuel injection system on modern bikes) provides the correct ratio of fuel and air, to allow the bike to run at its best.
Excessively lean carburetor settings can contribute to backfiring.
If the mixture is too lean, it may burn very slowly and unevenly.
This condition, in turn, may result in burning mixture remaining in the cylinder until the beginning of the next intake stroke when it can ignite the incoming air/fuel mixture.
The exhaust popping sound from a motorcycle exhaust is caused by excess fuel being ignited in the exhaust pipes.
The excess fuel is usually a result of an incorrect air fuel mixture in your engine.
Next time you hear that noise, no need to worry your engine is not going to blow up.
Backfiring from a motorcycle is also a common sign of bad spark plugs.
If you're hearing random loud pops coming out of your motorcycle exhaust, then you have a backfiring problem.