What Causes Backfire?
When the engine on your motorcycle has an emission system malfunction, such as an exhaust leak or a moment of running rich or running lean, backfire can occur.
When an engine is running rich, there is more fuel present than there is air. When an engine is running lean, there is more air than there is fuel. In either case, the result is an incomplete combustion where the fuel is ignited by the heat of the exhaust, causing the loud, popping noise.
The stock muffler that comes on a motorcycle is designed specifically to ensure the complete and proper operation of the engine. When an exhaust pipe is changed, this causes an unbalanced air-to-fuel ratio. The airflow into the motorcycle is increased because of the difference in pipe design and other specifics. This difference causes backfire in the exhaust.
Other causes of backfire are bad or weak fuel pumps, low fuel pressure, or clogged fuel filters. All three of these issues have a direct effect on the air-to-fuel ratio.
Tips to Prevent Backfire
There are multiple ways to stop a bike from backfiring that vary from inspecting and properly maintaining certain parts of a chopper to adding or replacing specific fluids.
Check Your Carburetor
Fuel can not flow properly through a dirty carburetor; this will cause a lean-running engine. If the carburetor is dirty, clean it with a high grade carburetor cleaner.
Check Your Jets
Jets clogged with debris can also prevent fuel from getting through the engine properly. If this is the case, your engine will run lean.
Add Fuel Injector Cleaner
If your motorcycle is fuel injected, using a high grade cleaner will help remove the dirt and debris trapped in your fuel lines. Consult your motorcycle's owner's manual for usage of a fuel injector cleaner for your model.
Change Fuel Grade
A low-rated fuel in your motorcycle can also contribute to dirty or clogged lines. A higher grade fuel can help to clear fuel lines and keep your fuel tank clean.
2001 Vstar 1100 Classic (sold), Cobra Slash Cut full exhaust, Dropped 1 inch with lowering links, ORK, 4.5 inch handlebar risers, Ultimate passenger seat, Passenger pegs moved forward 4 inches, Handlebar clock, KN air filter, Viking saddlebags, Additional rear lighting
Loose nut "me" behind the bars
2006 Harley Electra Glide Ultra Classic