[halcyononon]

As the title suggests, having some issues with backfiring (more accurately, after fire) on hard deceleration (i.e. 0% throttle) from above 6k rpm. Issue appears confined to when engine temp > approx. 80C.

To be clear, it doesnt sound like little "pops"....more like full on "BANG...BANG BANG..." sounds - scared the shit out of me the first time i heard it.

I have read that lean conditions can cause this:

"Backfiring on engine deceleration is most often caused by a lean mixture. Whatever is causing it creates a condition where the fuel-air mixture fails to ignite consistently in one or more cylinders. This allows some unburned fuel vapor into the exhaust manifold or stack. When the cylinder does fire, these unburned gasses are ignited, causing a backfire ranging from mild popping to loud gunshot cracks. "

Lastly, running the Zero map stops the backfiring, so I'm pretty confident its the tune.

Any ideas from anyone who has experienced similar? Not really interested in theories at this stage, just solutions.

 

[jwm2k3]

Some love the after fire, myself included. It hurts nothing, but I understand why you may want to rectify it. I've not tuned a PCV myself, but have read of others adding a bit of fuel at zero throttle and successfully eliminated the after fire. A bit of searching may turn up some threads. Either way, I think adding the fuel at zero is the path you need to take...

(Now to install and figure out the Bazzaz you sold me!) Good luck.

 

[Tuned]

This is the reason I dislike piggyback systems, they generally don't have any effect at zero percent throttle. So when you back the throttle off, it's going back to the ducati OEM map's on the ECU. Because the dyno tuner probably richened up the fueling everywhere else, there is a lot of unburned fuel hanging around. When you go from a rich map to a lean one all of a sudden, this is one of the side effects. A solution is to have the tuner not richen up the map SO much. Just go a tiny bit richer, just get that A/F a little bit smoother. If you go too far and try to do too much with a piggy back system, these are the results. You could also go all-out and have someone re-tune the stock ECU, that should resolve everything.

 

[halcyononon]

Some love the after fire, myself included. It hurts nothing, but I understand why you may want to rectify it. I've not tuned a PCV myself, but have read of others adding a bit of fuel at zero throttle and successfully eliminated the after fire. A bit of searching may turn up some threads. Either way, I think adding the fuel at zero is the path you need to take...

(Now to install and figure out the Bazzaz you sold me!) Good luck.

yeah, it's killing me - i've heard its not actually harmful too, so i'm conscious of how far to really pursue it. long story here, but it's not actually my bike, so I can only "recommend" solutions instead of just flashing the PCV myself.

anyway, i'll do a bit more digging and see what turns up. cheers.

ps. good luck with the Bazzaz. i think it comes with a tap for the temp sensor...probably something that would come in handy right about now!

 

[jwm2k3]

My 1198 Corse with Termi slip on kit does burble on decel at zero throttle. I can manually eliminate the burble with just leaving the throttle open a tad (bike still decelerating)....

Maybe try that...and its free!

 

[timmthehuman]

Old thread but I was curious about this. Mine pops only when the bike is above 150F on decel. I love the sound and want to mount a gopro facing the exhaust at night to see if it actually spits.

Glad to know it's not harming anything.