Backfire

[hulkss]

Let's try to get our terminology correct so we can discuss this stuff and know what is being said:

Backfire: A fuel-air explosion occurs in the induction system rather than inside the combustion chamber. Noise, flash, smoke etc. come back out the intake.

Decel Popping (Afterfire): Fuel air mixture that is not completely burned during combustion is ignited in the exhaust system. Noise, flash, smoke etc. come out the tail pipe.

 

[D94]

Ok tried the cig smoke to check for leak. Smoke wasn't moving anywhere erratic so I'm guessing I'm ok there. Got it to temp, and popping is coming from tailpipe. Decel pop Hulk? Am I to rich at 50%?

 

[D94]

Turned off completely still got pop. Went to 75% almost all gone. Also noticed the exhaust coming from the right side pipe was hotter than the left. The left was cooler.

 

[2015amberwiskie]

Make sure you don't have your o2 sensors backwards. The black plug is the rear and the grey is the front.

 

[hulkss]

First off, the box collector you get with a de-catted head pipe is not a good design. Nobody builds a new pipe like that. There is a big change in flow velocity just past the O2 sensors. The flow velocity drops dramatically and may even reverse toward the engine (reversion) under some conditions. This can make tuning and good drivability a challenge.

Second, the engine control module (ECM) learns as you ride. It will take time (50 - 100 miles) for it to forget old learned values and retune itself to the changes you have made. I'm using the SE street tuner and can erase the old learned tuning values when a new tune is loaded.

The ECM also has specific programming that attempts to control decel-popping. Be sure you are letting the throttle close completely on decleration so this programming will work as intended.

 

[Spazz]

Turned off completely still got pop. Went to 75% almost all gone. Also noticed the exhaust coming from the right side pipe was hotter than the left. The left was cooler.

Turn it up a little more.... see what it does..... also.. the right side will be a tad hotter since the flow on the left side runs thru the cross tube and will get less flow by design.... capping each end of the tips one at a time will illustrate this with the sound being different from each side as well

 

[D94]

I'm going to take it for a ride after work today, try to put some miles on. I'll leave at 75% and see if it goes away. If not I'll kick it up a bit, try again. Thx for all the input, I'll keep ya posted..