 off throttle popping
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Joined: Sep 2007
Posts: 26
Greenhorn
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OP
Greenhorn
Joined: Sep 2007
Posts: 26 |
to all, I just purchased an 02 America, when I bought it there were very loud shorties on the bike and I had them removed and the factory off road long pipes installed, they sound good when under power but during off throttle braking or down shifting etc, the popping is honorable, I looked up the bikes like mine, stock except for the off road pipes, and there seems to be different answers for this: I assume there is a long ans sorted story behind fixing this issue. so, If anyone would be so kind as to point me in the right direction, thanks
Instead of controlling the environment for the benefit of the population, perhaps its time we control the population to allow the survival of the environment - David Attenborough
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Re: off throttle popping
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Joined: Feb 2007
Posts: 23,219 Likes: 61
Fe Butt
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Fe Butt
Joined: Feb 2007
Posts: 23,219 Likes: 61 |
jetting.Probably lean the former owner may have not rejetted when he put the shortys on. Could be as easy as a few turns out on the mixture screws could be opening and rejetting. All depends where the carbs are jetted right now.
I learned all I need to know about life by killing smart people and eating their brains.
Eat right ,Exercise ,Stay fit, Die Anyway!
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Re: off throttle popping
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Joined: Sep 2007
Posts: 26
Greenhorn
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OP
Greenhorn
Joined: Sep 2007
Posts: 26 |
so the steps would be,
back the mixture screws out,, 1-2 turns???
if this does not fix it, then it may be the main jet size??
Idle jet size? or both, is there a jet size that should be in there with the off- road long triumph pipes?
thanks for the help
Instead of controlling the environment for the benefit of the population, perhaps its time we control the population to allow the survival of the environment - David Attenborough
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Re: off throttle popping
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Joined: Feb 2007
Posts: 23,219 Likes: 61
Fe Butt
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Fe Butt
Joined: Feb 2007
Posts: 23,219 Likes: 61 |
I would say first step would be to pull your plugs and look at them. geyish brown or light brown is good jetting, white is lean and , sooty or black is rich.
Dyno is better once you have it close so you know at what throttle or RPM range it is doing what and then adjust accordingly.
I learned all I need to know about life by killing smart people and eating their brains.
Eat right ,Exercise ,Stay fit, Die Anyway!
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Re: off throttle popping
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Joined: Sep 2007
Posts: 26
Greenhorn
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OP
Greenhorn
Joined: Sep 2007
Posts: 26 |
thanks, I will pull the plugs this week
jeff
Instead of controlling the environment for the benefit of the population, perhaps its time we control the population to allow the survival of the environment - David Attenborough
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Re: off throttle popping
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Joined: Dec 2006
Posts: 291
Adjunct
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Adjunct
Joined: Dec 2006
Posts: 291 |
I had same issues with what sounds like the same pipes. After I rejetted both and adjusted mixture, it still sounded like a cannon. All it took was 2 shims under the needles and bike runs AWESOME. Had it dyno'd after the fact and am running top performance with what I have. Easy job to put in shims.
Best looking black girl around!
2004 SM-spokes, solo seat, lowered rear, 14 in apes, bobber rear fender, no front fender. Flat black all the way around.
Jeff
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Re: off throttle popping
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Joined: Jul 2007
Posts: 89
Member
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Member
Joined: Jul 2007
Posts: 89 |
check this out www.dinqua.com. Its a carb calculator maybe it can help you out....
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Re: off throttle popping
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Joined: Jul 2006
Posts: 1,337
Learned Hand
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Learned Hand
Joined: Jul 2006
Posts: 1,337 |
Check for exhaust leaks.I'd suspect right at the slip on joint.
Pull the longs off and use a hi temp RTV (I like copper plus).
2002 Bandit 1200/ GSXR cams/ 1277 BB Kit/ Holeshot header and can/ 38mm flatslides/ a good head/lotsa hp/lotsa tq- lots of rear tires...
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Re: off throttle popping
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Joined: Jan 2006
Posts: 3,606 Likes: 2
Loquacious
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Loquacious
Joined: Jan 2006
Posts: 3,606 Likes: 2 |
ok here we go again...a PROPERLY tuned motor with high performance pipes WILL POP in DECEL....
From the mikuni site....
Note: It is normal for many high performance exhaust systems to
moderately backfire or pop when the throttle is closed from
mid-to-high rpm. In fact, one should expect a well-tuned high
performance engine to "pop" and "crackle" when the throttle is
closed at high rpm.
One thing that should be pointed out is that while the throttle may be
closed, leaning up the mixture, and it may take several revolutions of
the engine to build up a burnable mixture in the pipe, the engine will
still be running at a high enough RPM for the ignition advance curve to
be advancing the ignition. So, if you have an ignition system that
fires a waste spark, it's going to fire that spark during the valve
overlap period on one of your four cylinders, and that's enough to make
the exhaust backfire.
The popping is a result of the air/fuel mixture becoming very lean
when the throttle is closed and the engine is rotating well above idle
speed. It is also necessary that the exhaust system have rather open
mufflers.
Why This (normally) Happens:
1) When the throttle valve is in the idle position, fuel does not
flow out of the main system (needle, needle jet, main jet). Fuel is
only delivered to the engine by the pilot (idle) system.
2) The combined effect of the closed throttle and elevated engine rpm
is to create a fairly strong vacuum in the intake manifold. This
vacuum, in turn, causes a high air flow rate through the small gap
formed by the throttle valve and carburetor throat.
3) Under these conditions the pilot (idle) system cannot deliver
enough fuel to create a normal, combustible air/fuel ratio. The
mixture becomes too lean to burn reliably in the combustion chamber.
It gets sent into the exhaust system unburned and collects there.
4) When the odd firing of the lean mixture does occur, it is sent,
still burning, into the exhaust system where it sometimes ignites the
raw mixture that has collected ---- the exhaust then pops or backfires.
your engine, rather because it is an indication of lean and running so
can burn your exhaust valves everyone thinks it to be a bad thing.
Tuning your bike richer means an excess of fuel and very little to no
oxygen. Thus the unburned fuel passes through the pipe without ever
igniting. So you can think of the popping as a sort of environmental
control on your bike, combusting excess fuel that would have otherwise
not gotten burned.
THE VOICE OF REASON
per: Stewart
AF&AM/Shriner/Scoutmaster
130/45 TBS 2shim SS Uni 18/42
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Re: off throttle popping
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Joined: Dec 2005
Posts: 604
Adjunct
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Adjunct
Joined: Dec 2005
Posts: 604 |
You probably have 42 pilots, & these should be ok with the TORs.
Within that, it's just a matter of getting the screws adjusted to your satisfaction.
The point about sealing the slip ons is a good one.
I expect your secondary air injection has been removed or disabled.
If not, you'll need to do that.
Said Molly to James, that's a fine motorbike.
Richard Thompson
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Re: off throttle popping
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Joined: Feb 2007
Posts: 23,219 Likes: 61
Fe Butt
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Fe Butt
Joined: Feb 2007
Posts: 23,219 Likes: 61 |
Like Rob said some rumbling is good with less restrictive pipes. I took it as loud backfireing or excessive popping. In that case , jetting if you eliminate the rumble all together you are jetted wrong.
I learned all I need to know about life by killing smart people and eating their brains.
Eat right ,Exercise ,Stay fit, Die Anyway!
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Re: off throttle popping
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Joined: Jul 2006
Posts: 948
3/4 Throttle
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3/4 Throttle
Joined: Jul 2006
Posts: 948 |
I had my '06 rejetted waiting for TORS to come in and the popping drove me nuts! I got the TORS and the popping was louder but the dealer couldn't or wouldn't fix it. I finally(5,000 miles) got tired of the noise of the TORS and put the stock mufflers back on. For some reason the popping absolutely stopped. I put the TORS back on and it started again. I'm staying with the stock mufflers.
Redbike7
2006 America
No amount of skill can overcome gross stupidity. Ask me how I know...never mind, I forgot...
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 Re: off throttle popping
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Joined: Jun 2006
Posts: 2,626
Loquacious
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Loquacious
Joined: Jun 2006
Posts: 2,626 |
You didn't mention, has the air injection been removed? That caused popping on my Speedy. I could get foot-long flames out of my shorty mufflers at shutdown before I disabled the AI. 
Steelheart- '03 Speedmaster Black/Yellow
The Hayabusa Killa
16" Shorties/140 mains/Airbox drilled
Procom CDI
"There is no cure for Celibacy. But we can treat the symptoms."
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Re: off throttle popping
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Joined: Dec 2005
Posts: 604
Adjunct
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Adjunct
Joined: Dec 2005
Posts: 604 |
>I'm staying with the stock mufflers.
My take would be don't let the current state of tune dictate what pipes you run.
If you like the TORs outside of the decel pop, it's not that big a deal to get everything workin' together & to your satisfaction.
From your description, it sounds possible that the pilot screws have never been messed with.
Said Molly to James, that's a fine motorbike.
Richard Thompson
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Re: off throttle popping
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Joined: Jan 2005
Posts: 2,240
Oil Expert
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Oil Expert
Joined: Jan 2005
Posts: 2,240 |
Quote:
ok here we go again...a PROPERLY tuned motor with high performance pipes WILL POP in DECEL....
From the mikuni site....
Note: It is normal for many high performance exhaust systems to
moderately backfire or pop when the throttle is closed from
mid-to-high rpm. In fact, one should expect a well-tuned high
performance engine to "pop" and "crackle" when the throttle is
closed at high rpm.
One thing that should be pointed out is that while the throttle may be
closed, leaning up the mixture, and it may take several revolutions of
the engine to build up a burnable mixture in the pipe, the engine will
still be running at a high enough RPM for the ignition advance curve to
be advancing the ignition. So, if you have an ignition system that
fires a waste spark, it's going to fire that spark during the valve
overlap period on one of your four cylinders, and that's enough to make
the exhaust backfire.
The popping is a result of the air/fuel mixture becoming very lean
when the throttle is closed and the engine is rotating well above idle
speed. It is also necessary that the exhaust system have rather open
mufflers.
Why This (normally) Happens:
1) When the throttle valve is in the idle position, fuel does not
flow out of the main system (needle, needle jet, main jet). Fuel is
only delivered to the engine by the pilot (idle) system.
2) The combined effect of the closed throttle and elevated engine rpm
is to create a fairly strong vacuum in the intake manifold. This
vacuum, in turn, causes a high air flow rate through the small gap
formed by the throttle valve and carburetor throat.
3) Under these conditions the pilot (idle) system cannot deliver
enough fuel to create a normal, combustible air/fuel ratio. The
mixture becomes too lean to burn reliably in the combustion chamber.
It gets sent into the exhaust system unburned and collects there.
4) When the odd firing of the lean mixture does occur, it is sent,
still burning, into the exhaust system where it sometimes ignites the
raw mixture that has collected ---- the exhaust then pops or backfires.
your engine, rather because it is an indication of lean and running so
can burn your exhaust valves everyone thinks it to be a bad thing.
Tuning your bike richer means an excess of fuel and very little to no
oxygen. Thus the unburned fuel passes through the pipe without ever
igniting. So you can think of the popping as a sort of environmental
control on your bike, combusting excess fuel that would have otherwise
not gotten burned.
The EPA loves you man!
Pollution control!
Keith
Houston
Ridin'Texas
'04 Speedmaster
AI removed, Pingle, UNI Filter, 1 shim, straight-through slash-cut TORs, Stage 1 DynaJet, 140 mains, 3 turns, 16/42 final drive, 115K
2020 T120 Black
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Re: off throttle popping
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Joined: Jan 2005
Posts: 2,297
Oil Expert
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Oil Expert
Joined: Jan 2005
Posts: 2,297 |
Quote:
ok here we go again...a PROPERLY tuned motor with high performance pipes WILL POP in DECEL....
From the mikuni site....
Note: It is normal for many high performance exhaust systems to
moderately backfire or pop when the throttle is closed from
mid-to-high rpm. In fact, one should expect a well-tuned high
performance engine to "pop" and "crackle" when the throttle is
closed at high rpm.
One thing that should be pointed out is that while the throttle may be
closed, leaning up the mixture, and it may take several revolutions of
the engine to build up a burnable mixture in the pipe, the engine will
still be running at a high enough RPM for the ignition advance curve to
be advancing the ignition. So, if you have an ignition system that
fires a waste spark, it's going to fire that spark during the valve
overlap period on one of your four cylinders, and that's enough to make
the exhaust backfire.
The popping is a result of the air/fuel mixture becoming very lean
when the throttle is closed and the engine is rotating well above idle
speed. It is also necessary that the exhaust system have rather open
mufflers.
Why This (normally) Happens:
1) When the throttle valve is in the idle position, fuel does not
flow out of the main system (needle, needle jet, main jet). Fuel is
only delivered to the engine by the pilot (idle) system.
2) The combined effect of the closed throttle and elevated engine rpm
is to create a fairly strong vacuum in the intake manifold. This
vacuum, in turn, causes a high air flow rate through the small gap
formed by the throttle valve and carburetor throat.
3) Under these conditions the pilot (idle) system cannot deliver
enough fuel to create a normal, combustible air/fuel ratio. The
mixture becomes too lean to burn reliably in the combustion chamber.
It gets sent into the exhaust system unburned and collects there.
4) When the odd firing of the lean mixture does occur, it is sent,
still burning, into the exhaust system where it sometimes ignites the
raw mixture that has collected ---- the exhaust then pops or backfires.
your engine, rather because it is an indication of lean and running so
can burn your exhaust valves everyone thinks it to be a bad thing.
Tuning your bike richer means an excess of fuel and very little to no
oxygen. Thus the unburned fuel passes through the pipe without ever
igniting. So you can think of the popping as a sort of environmental
control on your bike, combusting excess fuel that would have otherwise
not gotten burned.
I like when Rob sends this every few weeks. Helps me remember that I am on the right site!!!
In Between the Dark and the Light..
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Re: off throttle popping
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Joined: Jan 2006
Posts: 3,606 Likes: 2
Loquacious
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Loquacious
Joined: Jan 2006
Posts: 3,606 Likes: 2 |
no kidding...it should be a sticky...or a pop up...if you type the words Pop and decel in the same sentence this will appear on your screen 
THE VOICE OF REASON
per: Stewart
AF&AM/Shriner/Scoutmaster
130/45 TBS 2shim SS Uni 18/42
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