Scorpion Exhaust & PCIII: Pops on de-acceleration?

[Thatguy331]

Hey all,

I bought a 2005 FZ6 with a Scorpion Exhaust and a Power Commander III. I just checked the PCIII and it is set with the data for a stock bike with Scorpion exhaust.

So when I'm de-accelerating, the exhaust sounds poppy... is that backfiring and is that bad, or just something to expect with the use of an after market exhaust like that?

Its new to me so I just want to make sure its *normal* and not *zomg its gonna blow*

 

[wrightme43]

Mine does it with out a pcIII. I may be wrong but I think its because the back pressure is a lot lower, and its pulling unburnt fuel air mix out and burning it in the exhaust.

 

[bmccrary]

It was always my understanding that poping on decel is a sign of being lean. I would try richening it up some and see if it gets better.

-bryan

 

[Thatguy331]

It was always my understanding that poping on decel is a sign of being lean. I would try richening it up some and see if it gets better.

-bryan

I'm not sure I really feel comfortable yet messing with the settings in the PCIII, I'm hoping maybe someone around here has gone through the same thing I am and have already altered their map accordingly and wouldn't mind sharing

If not, I guess I'll have to read up on it and try and do it myself. I'm surprised the PCIII map from their website for stock + scorpion would be that far off from what it should be???

 

[OneTrack]

I'd say it's part of the deal. My 06 with Scorpions, PCIII and K&N filter will pop on decel. I kind of like it now.
Check your exhaust system for leaks, btw..that will also cause backfiring in the exhaust.
The PCIII MAP for the above mods shows that the mixture is heavily enrichened at anything under 1500 rpm, which will cause the backfiring.
Look on the bright side...there's no baffles to blow out.
I suspect my backfiring is directly associated with my fuel consumption going from 45mpg to 35mpg.

Edited by me. Never attempt to talk about anything more technical than blue vs red when you're jet-lagged and after a few beers in Orlando.

 

[Hellgate]

It was always my understanding that poping on decel is a sign of being lean. I would try richening it up some and see if it gets better.

-bryan

It's the opposite, it's probably fat. The fuel is burning in the exhaust path, hence the pop. Typically this happens in a decel because the of the negative pressure in trailing throttle, the exhaust is over scavaging the engine. No biggy, sounds cool.

If I'm not mistaken the PCIII gives an air to fuel ratio. 14:1 is the goal, usually.

 

[OneTrack]

Either too lean or too rich will cause a "pop" in the exhaust. The difference is a lean "pop" will give you a bit of a burble with the occasional "snap, crackle and pop". Rich will do the same, except that it can and will give you a Big Bang that will blow off the end of the muffler from unburnt fuel gathering inside the muffler.

 

[wrightme43]

I can just go on my experince in the past. My bike smells rich, not overly rich, not unburnt rich, just rich. For all thats worth, though, its just my bike and my nose. No o2 sensor data to back it up.

 

[Nooj]

The Missus' bike does it with the Remus Revolutions she has on it. Sounds good, enjoy it, it's not damaging anything.

 

[reiobard]

My old bike did it with an aftermarket exhaust and the wifes bike also does it. Never really had any problems, i kind of like the popping.

 

[bmccrary]

In tuning the carbs on my fathers XR 600's and then on all my 2 strokes, poping has always ment it is too lean. But we can sit here and argue this all day, and not get anywhere so here is the fail proof test. This test will not lie and can not be argued, just pull one of the spark plugs. When you pull it out, if the tip is white then it is too lean. If the tip is a coco-brown color then you are ok, if the tip is darker than that coco-brown, then it is too rich.

So if I sound rude, I just woke up not too long ago and I didnt have any clean bowls for my ceral and my roommates are too @)#$Q$% lazy to clean up after them selves and run the dishwasher. That and its morning, I dont do mornings well.

-bryan

 

[AJ_rider]

I get the same deep pop/backfire when I decelerate also. From what I've heard it's normal with aftermarket racing exhausts. I dig it and it drives my R6 buddies crazy with their stock exhaust. :Flip:

 

[Trouble]

It does it on mine, and I love it. It only seems to do it when I close the throttle completely at about 6,000 rpm. Not so much above or below that. I can chose to do it or not. It has been known to upset a riding buddy when I was experimenting with it while riding with him. Speed up, slow down (pop pop pop), speed up, slow down (pop pop pop). I think it's a cool, approaching badass, sound.

 

[opds9091]

I have the scorps and PC111, when i start my bike it smells a little rich, then after it warms up and i go for a ride, i never have any poping or any bad sounds, just that wonderfull sound of loud pipes.