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| Drod | | Set |  |  | | Reg. Date | : | 29/08/2015 | | Posts | : | 53 | | Location | : | Yonkers, New York, United States |
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| | Posted : 29 Feb 2016 - 18:05 Post title : Popping on decel w/cat bypass | | | thought I'd start a fresh thread on this. tons of info on this site and I probably read all of it. but one thing that still continues to dodge everyone is the popping on deceleration with cat bypass. From what I have read so far on this site, it seems it really doesn't matter what cat bypass solution you go with, they all seem to have similar results when it comes to power and sound, but the popping on decel is still evident in all of these solutions. I read one rider was successful in eliminating the popping by re-installing the factory pipes. I may do that, but first i'd like to see if anyone has modified the recommended map #20359 to get better results using tuneecu. Or is a power commander the best option? if so, did the popping stop?
if so, can someone share the exact map changes to 20359 that helped them get better results?
my bike:
2014 t-bird 1600
cat bypass w/SS elbows
short TOR exhaust
map #20359
thunderbike high flow air intake kit
bike feels strong, has nice deep sound but does pop on decel from higher speeds. Not the end of the world but something I would like to minimize.
thanks guys.
| 2014 T-Bird ABS
Twin T handlebars
Shorty TOR w/map
Chrome controls
cat bypass
thunderbike hi-flow air intake
Quick release bar
custom LED lights
shock mount plate holder
Huge fan of SoA!
| | Post edited by Drod on 29 Feb 2016 - 18:07 |
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| davetac1 | | Thunderbird | | | Reg. Date | : | 06/09/2010 | | Posts | : | 8,379 | | Location | : | Haverhill, Ma., United States |
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| | Posted : 29 Feb 2016 - 18:43 Post title : Re: Popping on decel w/cat bypass (Re: Drod) | | | I believe the popping is caused from the lack of back pressure due to the change to performance or less restrictive mufflers,which leans out the air/fuel mixture.On carbureted systems,we use to up jet the carb[s] [richen the mixture] in order to prevent that popping on decel.On computer controlled fuel injected systems,usually if ya do the adaption procedure, that should recalibate the mixture and eliminate the popping.However,if it doesn't,then ,as you suggested,changing the tune may be what's required to eliminate it.
| | Post edited by davetac1 on 29 Feb 2016 - 18:45 |
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| edmontonstorm | | Jupiter | |  | | Reg. Date | : | 12/09/2014 | | Posts | : | 1,054 | | Location | : | Alberta, Canada |
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| | Posted : 29 Feb 2016 - 21:51 Post title : Re: Popping on decel w/cat bypass (Re: davetac1) | | | I have the hog slayer pipes (no cat) and a PCV and I have no popping at all anywhere. When I did I added some fuel to the 0-5% throttle range and all gone.
| Gloss Black 2013 Storm ABS - K&N (seal removed) - Mustang Seat - Hogslayer pipes - PCV-AT300
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| VABird | | Jupiter | |  | | Reg. Date | : | 28/09/2014 | | Posts | : | 1,373 | | Location | : | BEDFORD, Virginia, United States |
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| | Posted : 29 Feb 2016 - 22:17 Post title : Re: Popping on decel w/cat bypass (Re: Drod) | | | You're right
Cat bypass (elbows), Stock pipes, stock tune.
No popping.
Seems like the more money that gets thrown at this issue, the worse the problems get.
Expensive cat bypasses
Expensive aftermarket pipes
Map changes, PCVs.............
| The ride may be fun, but in the Great Scheme of things, it really is about the destination! John 3:16 
| | Post edited by VABird on 29 Feb 2016 - 22:18 |
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| edmontonstorm | | Jupiter | | | | Reg. Date | : | 12/09/2014 | | Posts | : | 1,054 | | Location | : | Alberta, Canada |
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| | Posted : 29 Feb 2016 - 23:22 Post title : Re: Popping on decel w/cat bypass (Re: VABird) | | |
VABird wrote:
You're right
Cat bypass (elbows), Stock pipes, stock tune.
No popping.
Seems like the more money that gets thrown at this issue, the worse the problems get.
Expensive cat bypasses
Expensive aftermarket pipes
Map changes, PCVs.............
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so what holds those heavy pipes up in the middle? they must bounce around a bit or hard on the headers etc? Have you tried the TOR tune with your set up?
| Gloss Black 2013 Storm ABS - K&N (seal removed) - Mustang Seat - Hogslayer pipes - PCV-AT300
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| satch1961 | | Chaac | | | Reg. Date | : | 27/09/2013 | | Posts | : | 583 | | Location | : | United States |
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| | Posted : 01 Mar 2016 - 01:11 Post title : Re: Popping on decel w/cat bypass (Re: Drod) | | | The popping if excessive can be annoying as shite. If you have a 1600 you may wanna try Silverfish's 1600 custom tune from tuneecu. My ride used to pop like crazy until i changed the tune
| 2010 1600 with 1700 cams; V4 custom tune; hi-flow filter; short TORS; rivco risers with spacers. Decat with elbows and baffles
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| AZCactus | | Taranis | |  | | Reg. Date | : | 01/05/2013 | | Posts | : | 4,512 | | Location | : | AZ |
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| | Posted : 01 Mar 2016 - 01:30 Post title : Re: Popping on decel w/cat bypass (Re: satch1961) | | | I think Leethal mentioned when decelerating use throttle ever so slightly...works for me!
| 2009 Thunderbird 1700 Big Bore
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| SAK1600 | | Set | | | Reg. Date | : | 13/03/2015 | | Posts | : | 93 | | Location | : | United States |
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| | Posted : 01 Mar 2016 - 02:51 Post title : Re: Popping on decel w/cat bypass (Re: VABird) | | | VABird wrote:
You're right
Cat bypass (elbows), Stock pipes, stock tune.
No popping.
Seems like the more money that gets thrown at this issue, the worse the problems get.
Expensive cat bypasses
Expensive aftermarket pipes
Map changes, PCVs.............
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I have the cat bypass elbows, stock pipes, stock tune and of course it pops on decel ! Of course I'm the exception !
Look up ''Exception to the Rule'' in the dictionary and you will see my fuckin face there!
I thought I read something about blocking off an SAI tube and that would cure the popping?
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| Tal | | Jupiter | |  | | Reg. Date | : | 30/01/2015 | | Posts | : | 1,074 | | Location | : | Christchurch, Canterbury, New Zealand |
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| | Posted : 01 Mar 2016 - 07:05 Post title : Re: Popping on decel w/cat bypass (Re: SAK1600) | | | When my Dyno man was tuning my R3, we had some popping on decal so he added fuel in the low 5% range...not too much, but it decreased the popping significantly...hasn't gone completely but that's the trick my son!
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| VABird | | Jupiter | | | | Reg. Date | : | 28/09/2014 | | Posts | : | 1,373 | | Location | : | BEDFORD, Virginia, United States |
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| | Posted : 01 Mar 2016 - 11:59 Post title : Re: Popping on decel w/cat bypass (Re: edmontonstorm) | | |
edmontonstorm wrote:
VABird wrote:
You're right
Cat bypass (elbows), Stock pipes, stock tune.
No popping.
Seems like the more money that gets thrown at this issue, the worse the problems get.
Expensive cat bypasses
Expensive aftermarket pipes
Map changes, PCVs.............
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so what holds those heavy pipes up in the middle? they must bounce around a bit or hard on the headers etc? Have you tried the TOR tune with your set up?
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The bulk of the weight of the stock mufflers is closer to the back where the hangers support it. The clamps seem to do an adequate job in the middle. I've never noticed any flexing.
I've been so happy with the results with the stock tune, and I'm not really after any more horsepower, so I've never attempted to change it. It is possible that the prior owner (bought with 1,150 miles on it) changed it, but I kind of doubt it.
| The ride may be fun, but in the Great Scheme of things, it really is about the destination! John 3:16
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| Drod | | Set | | | | Reg. Date | : | 29/08/2015 | | Posts | : | 53 | | Location | : | Yonkers, New York, United States |
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| | Posted : 01 Mar 2016 - 19:10 Post title : Re: Popping on decel w/cat bypass (Re: VABird) | | | thanks I do have the TORs map for the shorty TORs exhaust. (#20359)
the key is in making the right adjustments in the tune. (or replacing it with a tune that has the popping resolved)
i will look for the Silverfish tune to try that.. if someone has the link please provide...
also, where in Tuneecu do you adjust the low 5% fuel range?
| 2014 T-Bird ABS
Twin T handlebars
Shorty TOR w/map
Chrome controls
cat bypass
thunderbike hi-flow air intake
Quick release bar
custom LED lights
shock mount plate holder
Huge fan of SoA!
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| Hornet | | Jupiter | |  | | Reg. Date | : | 05/05/2013 | | Posts | : | 1,294 | | Location | : | United States |
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| | Posted : 01 Mar 2016 - 19:45 Post title : Re: Popping on decel w/cat bypass (Re: Drod) | | | Ok I'll ask how in the name of hell do this threads get all sideways wonky. And who's fault is it  
| You'll never be first but you might be next
2014 Commander
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| AZCactus | | Taranis | | | | Reg. Date | : | 01/05/2013 | | Posts | : | 4,512 | | Location | : | AZ |
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| | Posted : 01 Mar 2016 - 19:56 Post title : Re: Popping on decel w/cat bypass (Re: Hornet) | | | Hornet wrote:
Ok I'll ask how in the name of hell do this threads get all sideways wonky. And who's fault is it |
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Not me (for the record :)  it went south after my post 
| 2009 Thunderbird 1700 Big Bore
| | Post edited by AZCactus on 01 Mar 2016 - 20:03 |
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| Drod | | Set | | | | Reg. Date | : | 29/08/2015 | | Posts | : | 53 | | Location | : | Yonkers, New York, United States |
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| | Posted : 01 Mar 2016 - 20:37 Post title : Re: Popping on decel w/cat bypass (Re: AZCactus) | | | not me, i started the thread. it started when Sak1600 posted.
maybe an ipad or older browser post? Sak are you there??
how do we get it back? 
looks weird! I'm going back to work!
| 2014 T-Bird ABS
Twin T handlebars
Shorty TOR w/map
Chrome controls
cat bypass
thunderbike hi-flow air intake
Quick release bar
custom LED lights
shock mount plate holder
Huge fan of SoA!
| | Post edited by Drod on 01 Mar 2016 - 20:39 |
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| SAK1600 | | Set | | | Reg. Date | : | 13/03/2015 | | Posts | : | 93 | | Location | : | United States |
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| | Posted : 03 Mar 2016 - 01:27 Post title : Re: Popping on decel w/cat bypass (Re: Drod) | | | Yes I did it goddammit!! Its my fault!! My computer is old and I'm still using WindowsXP lol! Didnt want to admit to it but now Im caught, It was also me who effed up the Davetac on oil thread !! Well thats a load off, alright start piling on the abuse !
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| woftam4u | | Set | |  | | Reg. Date | : | 19/02/2015 | | Posts | : | 51 | | Location | : | Grafton, NSW, Australia |
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| | Posted : 03 Mar 2016 - 08:31 Post title : Re: Popping on decel w/cat bypass (Re: SAK1600) | | | I cocked one up too .... when i used the quote thingo. I went back and edited post, removed the quote and it was sorted. it could be something simple like that.... or mabee you have broken the whole interweb and the world will never be the same 
| Its hard to soar like a turkey when you are surrounded by gooses! 
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| Drod | | Set | | | | Reg. Date | : | 29/08/2015 | | Posts | : | 53 | | Location | : | Yonkers, New York, United States |
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| | Posted : 03 Mar 2016 - 16:50 Post title : Re: Popping on decel w/cat bypass (Re: woftam4u) | | | hey, we're back. no worries sak. didn't mean to call you out. it was more about figuring out how it happened. XP huh? even with 4gig of memory you can upgrade to Win7. trust me you'll be glad you did. i would probably stay away from Win10 untli you're forced to upgrade again.
anyway, as far as popping on decel is concerned, I chatted briefly with a Dyno Tune expert and he also confirms it could be caused by a lean air/fuel mixture configuration. There's a whole article on the cause. see article below. He says he can fix it and suggested I bring the bike over for a Dyno Tune and TuneECU map adjustment. I think this would be the best course of action. If nothing else, at least I will learn my exact hp and torque numbers post cat bypass, TORs exhaust and High Flow air intake and will be able to tell if these changes really made an improvement. Too bad I won't have "before numbers." it's just too much work to put everything back to stock.
has anyone done an actual Dyno test of their stock T-bird 1600? Triumph states these bikes should make 85hp and 108 lb of torque out of the box. Can anyone confirm? or are these numbers exaggerated?
About Backfires or popping in Exhaust
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.
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.
5) Completely stock Harleys do not do this until open-end mufflers, such as the popular Screamin' Eagle slip-ons, are installed. The exhaust must be both free-flowing and have an open exit for the popping to occur.
| 2014 T-Bird ABS
Twin T handlebars
Shorty TOR w/map
Chrome controls
cat bypass
thunderbike hi-flow air intake
Quick release bar
custom LED lights
shock mount plate holder
Huge fan of SoA!
| | Post edited by Drod on 03 Mar 2016 - 17:03 |
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