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P.J., Technician
Category: Motorcycle
Satisfied Customers: 750
Experience:  10 years as a mechanic and fabricator in a privately owned, local, custom bike shop.
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2012 FXDC all stock no modifications has only1500k is popping

Customer Question

2012 FXDC all stock no modifications has only1500k is popping on deceleration and seems hotter then normal,charged fuel drained ect. Checked for exhaust leaks ect. Before I get it to the dealer any ideas as to what could cause this popping? It's constant doesn't stop,Again it's a stock bike.
Submitted: 2 years ago.
Category: Motorcycle
Customer: replied 2 years ago.
I pulled the plugs they are ash white due to a lean mix,other then that I'm out of options..?
Customer: replied 2 years ago.
Also when cruising if you pull the clutch in while moving and rev the motor it will pop as well,I hope there's no internal issues.
Expert:  P.J. replied 2 years ago.
Hi, my name is ***** ***** I'll be working with you today.
It could be a faulty O2 sensor or wiring. If they are not working at all, they do typically set a trouble code and turn on the check engine light but it is possible that it is working just not sending the correct AFR information. If the lead in wiring and conduit is damaged there can be false readings as the sensor compares surrounding air oxygen content to exhaust oxygen content to produce an output voltage. Also, cracks can form around the O2 sensor bungs or threads which introduces oxygen downstream of the engine but upstream of the O2 sensor. This can cause an error in the O2 sensor output to the ECM as well.
An air leak in the intake manifold is also a possibility (and common) so, if you didn't check that yet, I would do that first. Look for the cap on the purge port as they commonly pop off. You can use a propane torch with a hose attached to direct propane gas around the intake manifold ports and seals. If there is a leak the propane gas will be drawn in while the bike is running and increase the idle speed. Don't let the gas enter through the air filter or you'll obviously get a false reading.
This is about all you can check without having a diagnostic computer to test operate the sensors, a gauge to test fuel pressure, etc.
I hope this helps. Thanks, P.J.