# Backfiring on deceleration no matter what i try?



## Josh (Nov 23, 2009)

I get a backfire on deceleration no matter how much air i let it have. I blocked off part of the intake to richer it up.. stills backfires.. I just upgraded to the 3 inch intake, and did the stock exhaust mod around the same time. With the 3 inch intake it is a little lean. I checked the plugs to confirm this. Even with it being lean, I still have a backfire when the engine break is doing its thing. This is very annoying and I cannot figure out a remedy for it. It just backfires no matter what. Any help/advice is appreciated. thanks


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## HeadC1 (Feb 11, 2009)

The backfire is actually from so much air sucking in and less fuel when you let off. Its not a bad thing but if you don't like it try just rolling off the throttle slowly.


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## Josh (Nov 23, 2009)

Rolling off the throttle slowly works just fine.. no backfire at all. Which I ment to include in my first post. So i'm assuming their is nothing i can do about it? Its just very annoying


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## NMKawierider (Apr 11, 2009)

Usualy from being too lean and/or a leaking exhaust gasket.


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## Josh (Nov 23, 2009)

I richen it up to the point of no power.. which still results in a backfire on deceleration. I replaced my exhaust gaskets not long ago and i still get this annoying backfire.. Maybe i still have an exhaust leak but i don't hear one, nor can find one.


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## phreebsd (Dec 16, 2004)

You can easily fix that if you have EFI.
note the RPM range it happens at and richen that RPM range at 0% throttle.
(this is all assuming you have a power commander and 08+ brute)


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## Josh (Nov 23, 2009)

Yup 09 fi brute.. But no power commander yet. That's the next on the list. Guess i'm going to get that sooner than i expected


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## phreebsd (Dec 16, 2004)

i wish i could get a PCV with autotune.
that's what you'll end up with unless you find a cheap used PCIII and go with it instead.


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## Josh (Nov 23, 2009)

Im hoping to find a cheaper used pc3.. You could always sell me yours and upgrade  haha


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## N2Otorious (May 10, 2010)

phreebsd said:


> i wish i could get a PCV with autotune.
> that's what you'll end up with unless you find a cheap used PCIII and go with it instead.


I went with the MSD Enhancer instead. Soo, MSD is another option.:bigok:


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## Josh (Nov 23, 2009)

It seems rich to me instead of lean? I'm no expert however. If it's blowing a flame out the exhaust, I'm thinking its rich and not lean? However still no power commander.


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## N2Otorious (May 10, 2010)

josh4290 said:


> It seems rich to me instead of lean? I'm no expert however. If it's blowing a flame out the exhaust, I'm thinking its rich and not lean? However still no power commander.


rich unburnt fuel will ignite in the exhaust pipes, lean pops go out the intake.

The confusion is when people call a pop in the exhaust a backfire, when it isn't. The lean pop will happen in the intake tract and back flow, hence "Back Fire".


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## Josh (Nov 23, 2009)

Well that seems to go against what people are saying on this thread. Not to cause problems, but I stated it my first post it backfires through the exhaust. Which people then come on here saying it's a lean backfire. It doesn't come out of the intake. It's the exhaust. I'm feeling more confused now then I was. It's blowing flames out the exhaust so I'm saying its rich. It doesn't make much sense for it to go rich all of the sudden when I throw on a 3 inch intake instead of the 2in that I have been running for a while. Intresting?


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## N2Otorious (May 10, 2010)

josh4290 said:


> Well that seems to go against what people are saying on this thread. Not to cause problems, but I stated it my first post it backfires through the exhaust. Which people then come on here saying it's a lean backfire. It doesn't come out of the intake. It's the exhaust. I'm feeling more confused now then I was. It's blowing flames out the exhaust so I'm saying its rich. It doesn't make much sense for it to go rich all of the sudden when I throw on a 3 inch intake instead of the 2in that I have been running for a while. Intresting?


I race cars, Turbo, Supercharged and of course Nitrous Drag cars. A fellow told me that not all of my car experience would apply to these bikes. Maybe this is one of them times.


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## Frosty19 (Apr 10, 2014)

Thought this would be a good place to ask my question. 

I have a brute (mods in my sig) and I'm having the odd single backfire at the exhaust on deceleration to low RPMs. I bought it used with the PCIII so I have no way to really adjust it, but I want to know if anybody has any suggestions on how to go about getting the proper software and cable to do so and what I could try adjusting in the map?

I thought it was a rich condition but I'm not sure of that after doing some reading.


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## chopermech (Dec 3, 2012)

Exhaust pipe leaks


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## Frosty19 (Apr 10, 2014)

I'll check over the exhaust again for leaks but I don't think there is any. 

Is there any tricks to finding leaksin the exhausts?


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## chopermech (Dec 3, 2012)

Soap an water on initial start up before it gets hot perhaps, they also make an exhaust joint sealer that comes in a tube


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## adamwedge (Jan 4, 2014)

Mine was backfiring because of a crack in my front header.


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## Coolwizard (Feb 28, 2009)

Ride at night, let someone follow you and see where the fire comes from when she pops


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## KawieKrizanek (Feb 2, 2014)

Mine was backfiringon decel because of a crack in rear header. Now the crack is back and it is doing it all over again.

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