Pop on decel
Cruiser
Joined: Jan 2008
Posts: 114
Likes: 0
From: Bellevue, WA
The foregoing explanations really only apply to carb bikes. The fuel injected ones actually shut off the injectors when you close the throttle. I suspect that they all have this pop to some extent but it only becomes really audible when you start monkeying around with a louder exhaust pipe or more free flowing intake which only exacerbates the condition. I have chased this decel pop thing ever since I brought my Dyna home and, while I have not managed to eliminate it through many combinations of pipes/intake/tuner I have managed to get a lot more performance out of my machine. I hate the popping not because I think it damages anything but because I remember as a young guy that it was a sign of a poorly tuned motor or a poorly designed engine build. Remember Glass-Paks? It seems to me that with modern ECM controlled ignition and fuel delivery there is no reason an engine should behave this way. All that said, I doubt it hurts anything and some people think it sounds cool. I know my neighbor isn't among them though because sometimes at 6 AM I get a pop on starting that sounds like a 357 magnum going off in my garage.
Outstanding HDF Member
Joined: May 2008
Posts: 2,166
Likes: 4
From: la
I would get a little pop with my Sideshots but after the BCT quiet baffles it went away. My Supermeg doesn't have any pop either. My T-Max has a decel pop mode and I have it turned off because it doesn't need it.
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Club Member
Joined: Feb 2008
Posts: 11,483
Likes: 39
From: Passaic County, NJ
Wanna laugh? I rode to my bud's house on Sunday and when I pulled up he said "I heard you close to two blocks away poppin and cracklin when you let off the throttle.
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Club Member
Joined: Feb 2008
Posts: 11,483
Likes: 39
From: Passaic County, NJ
So, the overall consensus is that the pop comes from unburnt gas hitting the air in the exhaust pipes. How could changing baffles eliminate that?
I've always wanted to know about all this, and I'm sure someone will come along and want to know the answer too.
I also appreciate all the info you guys put forward.
I've always wanted to know about all this, and I'm sure someone will come along and want to know the answer too.
I also appreciate all the info you guys put forward.
Last edited by SC-Longhair; May 3, 2010 at 08:27 PM.
Road Master
Joined: Jul 2008
Posts: 1,021
Likes: 2
So, the overall consensus is that the pop comes from unburnt gas hitting the air in the exhaust pipes. How could changing baffles eliminate that?
I've always wanted to know about all this, and I'm sure someone will come along and want to know the answer too.
I also appreciate all the info you guys put forward.
I've always wanted to know about all this, and I'm sure someone will come along and want to know the answer too.
I also appreciate all the info you guys put forward.
Cruiser
Joined: Dec 2007
Posts: 173
Likes: 0
From: W.V.
Pop pop
Really the pop starts up close to the exhaust port or just in side it .It is caused by revision of the exhaust gases back toward the engine.Changing anything inside the exhaust system changes revision thus changing popping on decel.Leaving your throttle cracked just a smidge will also make it pop more on an EFI motor.It will not hurt a damn thing.
The only pop I worry about is the occasional backfire on startup and the popping back through the carb that could actually cause some damage, IMO. The light popping on decel I hear through the SE II's is just music. Also why I don't run a radio - if I wanted that, my truck has a BEEEEG one!
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Club Member
Joined: Aug 2008
Posts: 753
Likes: 0
From: Yakima, WA
With the TTS I can tune it right out. Now all I have is a great sounding burble on deceleration.
Steve
Grand HDF Member
Joined: May 2007
Posts: 3,553
Likes: 17
I've found the exact opposite to be true in my case. If I hit it hard and immediately let off all throttle I'll get some gurgling and an occasional muffled pop. If I let off the throttle more slowly and keep just a touch of throttle on it decels with out the sound of anything popping/gurgling.