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Discussion Starter #1

I am getting some bad very loud back fire on deceleration!

I have after market pipes.
I have a stock air cleaner.
I do not have a power commander.
( Well I did .. I removed it to test both have back fire. )

I replaced the two exhaust gaskets.
I used the "marble" Trick at the air cleaner- NO help.

I removed the entire EPA system.
Blocked the two air intakes at the heads with rubber stoppers.

I really like to use the gears for deceleration !
Instead of the brakes ! But Get WAY to much back fire to do that!

HELP ????
 

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When you had the Power Commander on did you try increasing the fuel levels during deceleration? That's the only thing that ever worked for me while running premium gas.
 

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Sounds like you covered everything you could so far. Time to get the controller back on it and do some fine tuning of it to try to get it fixed maybe. You may have a bad injector allowing fuel to drip into the cylinder and that may cause this too. Take the injectors out and test them to see if one of them is plugged up and dripping instead of spraying.
 

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wocka, wocka, wocka
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run some seafoam in a 1/2 tank of gas. put 8oz in last 2 gallons. see if that skrubs opens up them injectors.
 

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Discussion Starter #5
When you had the Power Commander on did you try increasing the fuel levels during deceleration? That's the only thing that ever worked for me while running premium gas.
Sounds like you covered everything you could so far. Time to get the controller back on it and do some fine tuning of it to try to get it fixed maybe. You may have a bad injector allowing fuel to drip into the cylinder and that may cause this too. Take the injectors out and test them to see if one of them is plugged up and dripping instead of spraying.
run some seafoam in a 1/2 tank of gas. put 8oz in last 2 gallons. see if that skrubs opens up them injectors.
Ok guys will give it a try .. thanks
Its really bad :( Driving me and the other riders crazy :(
Forgot to say I am even running 87 gas also !
 

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What exhaust do you have? I had the cobra 2 in 1. Tried everything mentioned and the only thing that worked was retuning the power commander back to a stock setting and then adding a bit of fuel during deceleration. Guys at power commander helped me with it.



Sent from Motorcycle.com Free App
 

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I just traded my 2009 for a voyager and from what I learned the last 5 years is you will never get it gone completely. I had 3" straights and stock intake. did the marble thing and no help and did the sea foam and no help the best was make sure the throttle is closed on the down shifts. read lots of talk bout it and there is something with the 08-10 that it never goes away
 

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Does the V2K have an idle adjustment screw? On a lot of models of bikes, decel popping can be a product of a too-low idle. One of the guys I ride with has an older Victory with that same issue. If he raises the idle, it goes away. But he wants it to "sound cool" so he drops it down to this near-stall and the machine gun starts. (Between you and me I don't think either his "About to stall out" idle or the decel popping sound very 'cool'.)

If the idle is user adjustable you might see if you can't bump it up a bit. That was the "fix" for the popping on the 900's. Getting the idle in the correct range (950-1050) as a lot of owners liked to drop the idle way down. I realize those are two very different engines but the idea is the same; they both burn air and fuel! It's my perception that the decel popping might be too much fuel making it's way into the exhaust and igniting. Maybe more fuel from the fuel processor makes it too rich to even pop, I'm surprised that works (not doubting that it does, just surprised that it does). But part of the reason it might be too rich at idle is that the idle circuit is expecting a lot more air (from a more open idle throttle position) than it's actually getting.

Just food for thought. The Vaquero does this too but I've got stock exhaust (for now) so it's just a manageable burble.
 

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Romans may be on to something. The 2K has an adjuster on the left side of the air cleaner. Not saying that is it, but could be a possibility. Also need to spin enough to send oil to the top end. I had a Yamaha V-Star 1100 that the PO when I bought it was "tuning it to sound like a Harley" (his words not mine). Bike ran good, but if you let the throttle all the way off and starve it of air it would backfire like crazy and stumble on take off unless you wicked it up before you let out the clutch. Bike sounded like it was idling at 500 rpms or so. I pulled off the side of the road and turned it back up to where I thought it should be and rode it back.
 

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Share your Power Commander Map for review. You can copy and past the fuel numbers or share the file. It would be interesting to see where it was set in the "0" throttle ranges at 1000 RPM and above.
 

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yep I had hard chrome pipes on mine, I played with the idle and no cure. I put a marble in it too. with that said when it was new with stock exhaust you could hear a muffled popping, with open pipes it is louder. the new voyager is the same and I expect when I put slip-on's on it will be the same story. like I said just try to keep the throttle closed, even a small crack open would increase the popping lots. hope this helps, Mike
 

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Discussion Starter #13
Way less backfire now! And Sounds Better too !

Well I decided to try this MOD on the baffles on my Pipes ..
And it has helped ! Way less backfire now! And Sounds Better too !
Way cool Mod. Cost me $8-9 for the fiberglass and took about 1 hour!

https://www.youtube.com/watch?v=75DK0uzBM80

I will still try and play with the power commander later this week.
 

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I got a wild hair and filled up with regular gas, I think it was 86 octane, instead of the 91 or 92 I use in all my other bikes. No pinging and decreased the popping by about half! I know this is strange, but it is the case with my V2K. And my bike sounded like a machinegun when I downshifted, and popped when I upshifted too.
 

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wocka, wocka, wocka
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I got a wild hair and filled up with regular gas, I think it was 86 octane, instead of the 91 or 92 I use in all my other bikes. No pinging and decreased the popping by about half! I know this is strange, but it is the case with my V2K. And my bike sounded like a machinegun when I downshifted, and popped when I upshifted too.
doomies,, its not rocket science as many would have you believe. pop in the pipe is the result of unburnt fuel accumulating and reaching its LEL (lower explosive limit) this is accomplished (on purpose per epa) by AIS introducing fresh oxy air into the exhaust when you decelerate. Those nipples on top of the heads feed reed valves that open with negative pressure waves..

the cure is to shit can the entire AIS system and plug those nipples. the Oxy rich fresh air component goes bye bye.
next is to rid of stock exhaust sys with humongous catalyzers which "catch" all the unburnt fuel..
Tres, run standard 89 octane fuel as it is perfectly suited for this motor as it ignites earlier (and to think that many play with their timing to achieve this, but insist on slow ignition/burn 92) and burns more thoroughly leaving less unburnt fuel in the exhaust stream to go POP..

so all the mystery and voodoo you read about this is just that. and yes this bike is equipped with idle adjust on rite side. factory she is ~900rpm is fine. no need to sound like a hardly, its a 4 valve head. why would you want to be mistook for one them farm tractors? next somebody mite think you was a greaseball dirtbag..
 

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Voodoo

Gee Ponch, yer takin' all the voodoo and mystery out of ridin' with science!

I'm getting ready to change out the factory coolant in my '07, which will mean pullin' off the gas tank. I'll attend to the AIS then.

I know you got rid of your V2K. Glad you're still postin' here.
 

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I got a wild hair and filled up with regular gas, I think it was 86 octane, instead of the 91 or 92 I use in all my other bikes. No pinging and decreased the popping by about half! I know this is strange, but it is the case with my V2K. And my bike sounded like a machinegun when I downshifted, and popped when I upshifted too.
I had the same experience on my 900. 87 ran good. I run 93 in the Vaq and get popping (but it's barely audible, still stock exhaust). I'm leary of running below the manufacturers minimum (87 was the minimum on the 900), but it sure does work.

Like Ponch said, lower octane fuels burn earlier and easier. There are a few things higher octane fuels are, and a lot of things they aren't. They aren't cleaner, nor do they somehow generate more power (they can enable more power by allowing an engine tuned to take advantage of it's resistant to knock, but in itself, it doesn't have any more energy). So if your bike runs better with 87, then... there's your answer!

There's an equivalent AIS system in the 900 but I never fooled with removing or plugging it. Running 87 and I never got any popping.
 

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Ponch is certainly the resident expert on the V2K. However, I tried everything mentioned. 87 octane and reprogramming the Power commander to add a bit of fuel on deceleration were the only things that worked. I had stock air filter and a cobra 2 in 1 exhaust. Once I did that , she sounded and ran perfect. Mpg jumped also.
 
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