Now that the election is over

[BlacktopTravelr]

let's get back to bikes and other normal things like heaters to warm me up.

The 800 has a small backfire when I let off the throttle to shift, anybody know what causes that? I could shift without letting off the throttle I guess and the backfire wouldn't happen. [space]

[Suzuki Johnny]

A backfire is an explosion that occurs either in the intake or in the exhaust of your motorcycle. This explosion is supposed to occur in the combustion chamber, and when it doesn't, there is an interruption in your engine's operation. It is possible to see a short-lived flame coming from the exhaust. Whether it happens in the intake or exhaust, the loud noise that results can be momentarily startling to the rider and those nearby.

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.

[jonnycando]

I am thinking exhaust leak. Also intake leak causing an excessive lean condition.

[BlacktopTravelr]

hmm, it could be a leak but it sounds like it is coming from the right pipe which doesn't have the exhaust leak. It could be a dirty air filter. [space]

[Suzuki Johnny]

Check it out and get back with us John....I for one am curious as to what was causing the problem

[BlacktopTravelr]

Johnny, I'm leaning towards the exhaust leak as the left pipe rattles and has for a long time but it didn't pop. But then it could be the cooler fall air causing it to backfire.

[Suzuki Johnny]

Aha...never gave that a thought.