Backfire at low rpm

Zill · Mar 23, 2012

2011 fe 390 with just over 3 hrs of life. I get a backfire at low rpm and applying the throttle. it has happened 5 or 6 times. Any ideas?

Ruger · Mar 23, 2012

What modifications have been made to the bike? Has it still got the factory pipe and muffler, and has it still got the factory emission controls? If modifications have been made to change gas flow, it probably explains this. The solution is having your dealer upload the performance map to your ECU.

Also, double-check your air filter. If it isn't seated properly and sealed around the edge with air filter grease, excessive airflow around the filter and not through it may be making your bike run lean. An excessively lean mixture will produce the symptoms you described.

Zill · Mar 28, 2012

No mods it is bone stock, I will check the filter that sounds logical. Thanks.

Torque Monster · Mar 28, 2012

Ruger said:
Also, double-check your air filter. If it isn't seated properly and sealed around the edge with air filter grease, excessive airflow around the filter and not through it may be making your bike run lean. An excessively lean mixture will produce the symptoms you described.

I hope that at low RPM you air filter isn't a restriction, maybe if it were dirty but otherwise it should have no restriction on the system IMO seated or otherwise.

If the bike is not completely warmed up they will do what you are describing pretty easily, and it takes longer to warm up that me or most people give them.

Ruger · Mar 28, 2012

Torque Monster said:
Ruger said:

Also, double-check your air filter. If it isn't seated properly and sealed around the edge with air filter grease, excessive airflow around the filter and not through it may be making your bike run lean. An excessively lean mixture will produce the symptoms you described.

Click to expand...

I hope that at low RPM you air filter isn't a restriction, maybe if it were dirty but otherwise it should have no restriction on the system IMO seated or otherwise.

If the bike is not completely warmed up they will do what you are describing pretty easily, and it takes longer to warm up that me or most people give them.

Um, I said "excessive airflow" not "restriction." Those are opposites.

Torque Monster · Mar 28, 2012

Ruger said:
Torque Monster said:

Ruger said:

Also, double-check your air filter. If it isn't seated properly and sealed around the edge with air filter grease, excessive airflow around the filter and not through it may be making your bike run lean. An excessively lean mixture will produce the symptoms you described.

Click to expand...

I hope that at low RPM you air filter isn't a restriction, maybe if it were dirty but otherwise it should have no restriction on the system IMO seated or otherwise.

If the bike is not completely warmed up they will do what you are describing pretty easily, and it takes longer to warm up that me or most people give them.

Click to expand...

Um, I said "excessive airflow" not "restriction." Those are opposites.

Torque Monster · Mar 28, 2012

Ruger said:
Um, I said "excessive airflow" not "restriction." Those are opposites.

Um kay, that is impossible as the airflow is controlled by the butterfly below the airfilter - airfilter just cleans the air.

Ruger · Mar 28, 2012

Airflow is affected by whatever is in the intake tract including whatever is in the air and the air itself. If the air filter is clogged with crap, it'll affect airflow. If the air filter comes loose, it'll affect airflow. If the air is zero degrees, full of dust, or full of water vapor, it'll affect airflow. Etc. Not just the butterfly.

Torque Monster · Mar 28, 2012

Filter on or off, didn't affect my dyno runs or FI settings.

Ruger · Mar 29, 2012

Noted!

erniebearskin · Apr 6, 2012

Exact same problem, backfiring when rolling off throttle, couple of stalls, lots of popping. 2011 390, 40 hrs. Started hapening after a couple hard hours of moutain enduro????????? Is there alternate maps (less lean) from dealers?

toopilot · Apr 7, 2012

you need the latest ECU curve, Just had mine done no more backfire! The reason it backfires is because it runs too lean. Have the ECU reflashed and all will be well
Tim

erniebearskin · Apr 8, 2012

Any recomendations on what to do if my dealer tells me "they arent aware of an updated map"? Is there a map version or something I can reference to educate my dealer. I know, kind of sad.

erniebearskin · Apr 11, 2012

Hi gents, any help on how I can assist in directing my local dealer on what "competition" map I need for my 2011 fe390 to cut down on some of the popping backfiring etc?

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Backfire at low rpm

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