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Discussion Starter · #1 ·
I always had decel popping when my 07 DX was stock, but it is much more noticeable once I cut my stock pipes into shorties. I had the bike dyno tuned, but it appears they only worked on the acceleration, not the deceleration. Anyone have any recommendations for fixing the heavy decel popping, like a good map for the following set up?

PCIII
v-modded pipes cut to shorties
Topless
K&N filter
 

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Dilligaf
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5,393 Posts
Bacon said:
I always had decel popping when my 07 DX was stock, but it is much more noticeable once I cut my stock pipes into shorties. I had the bike dyno tuned, but it appears they only worked on the acceleration, not the deceleration. Anyone have any recommendations for fixing the heavy decel popping, like a good map for the following set up?

PCIII
v-modded pipes cut to shorties
Topless
K&N filter
Post your map and maybe we can fix it.
 

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1130cc.comaholic
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13,241 Posts
I just found this map the other day and have been using it....
http://www.1130cc.com/forums/showpost.php?p=1047421&postcount=77
my bike doesn't have much of the decel pop now but every once in awhile on decel it will backfire. Before it was a small pop over and over but now it's a very loud backfire sometimes.

anyway you could try that map and see how it works with yours (I like it better than the force map power commander has) but if anyone could tweak that one, that would also be good :thumb:
 

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Deputy Rally Rouser
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1,795 Posts
Interesting thread--I (Danno) recently put on a set of SE double barrels that were "D-Modded". They sound awesome, but they do pop occasionally on deceleration (mostly when I am decelerating to a stop from highway speak and downshifting). It's not all the time, and only when I have downshifted into a relatively high RPM. I actually kinda like the "crack" that I get now and then. My question is, though, is this harmful? I didn't really think it was, since (for example) a lot of hot rod cars with straight pipes do that too. :confused:
 

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_NoHighLikeMostHigh_
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2,180 Posts
Bacon said:
I always had decel popping when my 07 DX was stock, but it is much more noticeable once I cut my stock pipes into shorties. I had the bike dyno tuned, but it appears they only worked on the acceleration, not the deceleration. Anyone have any recommendations for fixing the heavy decel popping, like a good map for the following set up?
The less back pressure the more fuel you need for decel. With my SE2 and D&D pipes I had the 1st column as high as 35% and no decel on popping. My dad is now using my pipes and MAP and there has never been one decel on popping. Richen up the 1st column of your MAP (0% throttle in the range of RPMs where it pops).
 

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Gigs07DX
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469 Posts
Decel popping

I am having the same issues with my 07 DX, V-modded pipes, pc111, and totally open air box with K&N filter. I was mapping the Zero column today, and found that only way to eliminate the poping, was to take fuel away, not add. I have eliminated about 90% of popping that accured between the 2-4000RPM range. Chopper Steve told me the same thing, only two things can cause decel pop, loose pipes at the head, or too rich.
 

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Kaboom
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4,336 Posts
I have mine dyno tuned from Fuel Moto, and am very happy with the results (109 RWH/79 ft. lbs TQ, smooth lines all thru the power curve)......and it pops on decel a little.
It actually sounds very cool.
If yours is tuned right, there is not a problem with popping on deceleration.
 

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Dilligaf
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5,393 Posts
gigs04vrod said:
I am having the same issues with my 07 DX, V-modded pipes, pc111, and totally open air box with K&N filter. I was mapping the Zero column today, and found that only way to eliminate the poping, was to take fuel away, not add. I have eliminated about 90% of popping that accured between the 2-4000RPM range. Chopper Steve told me the same thing, only two things can cause decel pop, loose pipes at the head, or too rich.
There is only 2 ways to stop decel popping, one is to cut all the fuel at zero ie -99 and the other is to add it at zero up to around 5500 rpms till it stops. If you cut the fuel the bike will decelerate harder and feel like it is going to stall till it hits 1500 or 1200 rpms where there needs to be fuel to keep the bike idling.
 

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Dilligaf
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5,393 Posts
gigs04vrod said:
I am having the same issues with my 07 DX, V-modded pipes, pc111, and totally open air box with K&N filter. I was mapping the Zero column today, and found that only way to eliminate the poping, was to take fuel away, not add. I have eliminated about 90% of popping that accured between the 2-4000RPM range. Chopper Steve told me the same thing, only two things can cause decel pop, loose pipes at the head, or too rich.
What causes Backfiring
"Deceleration Backfiring" is the most common backfiring that occurs when you change down and throttle off.
"In general, backfiring on deceleration (as opposed to acceleration) is generally caused by a lean condition in the pilot circuit. What happens is that the mixture leans out enough to where is fails to ignite consistently. This, in turn allows some un-burnt fuel to get into the exhaust pipes. Then when the engine does fire, these un-burnt gasses are ignited in the exhaust pipe, causing the backfire.
 

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Gigs07DX
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469 Posts
Decel popping

Sounds Like SPAZ know exactly what causes it and how to fix the issues, Only question I have is if I add fuel in the zero column, up till 5000, arent I going to run super Rich!!!

Spaz, Thanks For the info, sure it will help. My bike does exactly that, it slows much quicker being that I dropped the fuel in the zero column
 

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Dilligaf
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5,393 Posts
gigs04vrod said:
Sounds Like SPAZ know exactly what cvauses it and how to fix the issues, Only question I have is if I adding fuel in the zero column, up till 5000, arent I going to run super Rich!!!

Spaz, Thanks For the info, sure it will help. My bike does exactly that, it slows much quicker being that I drop the fuel in the zero column
It will only run richer while off the throttle same as a carburator basically where fuel still runs even though your not on the throttle so that the engine stays running. If you set the zero throttle to cut all fuel your engine is not running it is just dry cycling. Also remember that the numbers in the map for a pc3 represent percentage of fuel added over the stock settings.
 

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Premium Member
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krodwi said:
I have mine dyno tuned from Fuel Moto, and am very happy with the results (109 RWH/79 ft. lbs TQ, smooth lines all thru the power curve)......and it pops on decel a little.
It actually sounds very cool.
If yours is tuned right, there is not a problem with popping on deceleration.
:them:
 

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Ricky Love MooreHead
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Does the popping (backfire) hurt anything? I have a little still on mine. I have added fuel from 1500 to 3500 and it's better, but still there.
 

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Guitar, not Gator
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On a carburated Airhead, that's usually a sign of a leaking intake gasket either the rubber slip ring to the carb or the O-rings between the manifold and head.

I wish I knew a little more about the Rod's
 

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Dilligaf
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5,393 Posts
QuickTripp said:
Does the popping (backfire) hurt anything? I have a little still on mine. I have added fuel from 1500 to 3500 and it's better, but still there.
No it doesn't hurt anything unless it's like one very big back fire like turning your car off but leaving it in acc where it still feeds fuel going down the road then turning the key back on and blowing your exhaust system off. :spank: Ah I remember those days and how expensive and how dirty the work was replacing the exhaust, but it definately scared the crap out of people.:laugh:
 

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Dilligaf
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5,393 Posts
gtrman66 said:
On a carburated Airhead, that's usually a sign of a leaking intake gasket either the rubber slip ring to the carb or the O-rings between the manifold and head.

I wish I knew a little more about the Rod's
It's the same on the rods but there can't be that many intake gasket leaks on the new v-rods that people have now and complain about decel popping. If it was from leaks there would be a major recall because all the new ones do it. You can still have an intake leak or a leak at the exhaust gasket or a leak midway down one of your pipes and it will pop on decel on a vrod just like an airhead.
 

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Premium Member
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My Dad had a "64" Panhead with the manual spark retard on the left grip like my "61". His had dual fishtail exhaust and he loved to come roaring down the street in 2nd gear at about 45 mph and let off the gas and retard the spark. It sounded like a shotgun going off.
 

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_NoHighLikeMostHigh_
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2,180 Posts
I guessed no one believed me :). When I used to tune carb bikes same thing, once you open up the air filter and pipes you get the lean decel popping. Needed to pop the caps off the air fuel mixture screws and richen it up.

Yes, putting the column to -99 will work, but to me that is not the right way to do it.

What also helps is having a CO2 sensor that you can stick in the exhaust. I have one of these that I usually use also but only for setting up the bike for idling and blipping the throttle.

With my turbo now, I just went with the MAP from Trask. Works great.
 

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Guitar, not Gator
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Spaz said:
It's the same on the rods but there can't be that many intake gasket leaks on the new v-rods that people have now and complain about decel popping. If it was from leaks there would be a major recall because all the new ones do it. You can still have an intake leak or a leak at the exhaust gasket or a leak midway down one of your pipes and it will pop on decel on a vrod just like an airhead.
My R has never popped, even when I put on a CFR and Gil's box for a while. I sold the CFR and kept the Gil's box on there (no changes) and it still runs great.

It wouldn't be the first time the moco dragged their feet on a recall. How many riders got 3rd degree burns before they offered to fix the heat shield?

The other bummer with my airhead, was the pop sometimes blew the vacuum line off the petcock and shut off my gas... always a fun (and hot) job to fix roadside.
 

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Dilligaf
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Sounds like it would be a good poll to see just how many new unmodified bikes have decel popping. I know my D did until I richened her up.
 
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