The Great Decel Popping/Backfire Debate
Thread Starter
|
Road Warrior
Joined: Nov 2006
Posts: 1,439
Likes: 2
From: Lancaster, PA
The Great Decel Popping/Backfire Debate
I read all the time that if you are getting popping/backfire on decel then you are running lean. Who ever came up with that? [:'(]That is sofar far from the truth it isn't even funny. If anything your more likely to running on the rich side if getting the decel pop/backfire. As some/many (time will tell)of you knowa pop/backfire out the pipe is nothing but O2 being sucked in to the exhaust somewhere i.e. a leak and igniting unburned fuel in the pipe, the end result is a small explosion/pop/backfire. If your running lean, not enough fuel, then how does that even make sense, Decel popping equals lean? [:'(]Ever go to your local short track and watch the Sprints, Modifieds, Latemodels, etc. Man when they let off before the turn, that methanol lights up such a pretty blue, with the air being sucked in and the fuel being burned off. 
Banned
Joined: Feb 2007
Posts: 279
Likes: 0
From:
RE: The Great Decel Popping/Backfire Debate
If a person went by your theory then all of these lean running 07's would run better after installing better flowing air cleaners and pipes with no other fuel alterations because they would now be running even leaner than they were stock and would have no decel popping and if they did then they would need to lean them out even more because as you said they must be running rich. A lot of people on this forum including my self have eliminated the decel popping after installing after market pipes, air cleaners and ecm maps by adding fuel to the f/a ratios at the rpms where the popping is taking place. According to you we should have made the decel popping worse. And no I didn't have any air leaks at the headers, mufflers or intake.
Cruiser
Joined: Mar 2007
Posts: 212
Likes: 0
From:
RE: The Great Decel Popping/Backfire Debate
Zippers Performance Parts sells a piece that you put into the left side split of the rear cylinder header pipe (if so equipped). It's called a pop-stopper. What it does is constricts the pipe down to a hole the size of a dime. Since most exhaust goes out the right side anyway it even helps the stock pipes act like a 2 into 1 system. Now I have not tried the product and what I just spouted is all theory. But it sounds good. I couldn't find the product on their website either but I have one in my hand. Paid $7 for one but didn't install it when I put on my V&H Ovals. I'm also running PCIII and have not heard any backfiring.
From the package:
Reduces inbound fresh air reversion which causes excessive decel backfiring. Remove left muffler, install in headpipe at muffler joint.
If you wish to call and discuss the product with them their number is 410-579-2828. Let us know if you end up using it. I'd like to quit moving it from one part of my workbench to another. Either install it or throw it in the garbage.
From the package:
Reduces inbound fresh air reversion which causes excessive decel backfiring. Remove left muffler, install in headpipe at muffler joint.
If you wish to call and discuss the product with them their number is 410-579-2828. Let us know if you end up using it. I'd like to quit moving it from one part of my workbench to another. Either install it or throw it in the garbage.
Thread Starter
|
Road Warrior
Joined: Nov 2006
Posts: 1,439
Likes: 2
From: Lancaster, PA
RE: The Great Decel Popping/Backfire Debate
ORIGINAL: cowboyglide
If a person went by your theory then all of these lean running 07's would run better after installing better flowing air cleaners and pipes with no other fuel alterations because they would now be running even leaner than they were stock and would have no decel popping and if they did then they would need to lean them out even more because as you said they must be running rich. A lot of people on this forum including my self have eliminated the decel popping after installing after market pipes, air cleaners and ecm maps by adding fuel to the f/a ratios at the rpms where the popping is taking place. According to you we should have made the decel popping worse. And no I didn't have any air leaks at the headers, mufflers or intake.
If a person went by your theory then all of these lean running 07's would run better after installing better flowing air cleaners and pipes with no other fuel alterations because they would now be running even leaner than they were stock and would have no decel popping and if they did then they would need to lean them out even more because as you said they must be running rich. A lot of people on this forum including my self have eliminated the decel popping after installing after market pipes, air cleaners and ecm maps by adding fuel to the f/a ratios at the rpms where the popping is taking place. According to you we should have made the decel popping worse. And no I didn't have any air leaks at the headers, mufflers or intake.
Not sure how you go about getting a pop/backfire without unburned fuel and O2 being present? I have TD's on my bike, SE air cleaner Rush 1.75's and i get a pop/backfire out the left pipe quite often. Bikes running great, plugs are perfect color. I reach my hand down to where the muffler clamps on to the end of the tail pipe, black carbon on my fingers. It's sucking in some air where the left muffler clamps on to the exhaust pipe. No lean condition for me. But i do get a pop out of the left side. 
Tourer
Joined: Jun 2006
Posts: 469
Likes: 0
From: Motown
RE: The Great Decel Popping/Backfire Debate
I do think the decel popping is caused by a lean condition. My understanding is that it is caused by unburned fuel (in the exhaust gasses) igniting in the head-pipe. I may be wrong, but I thought that richening the fuel-air mixture brings the amount of unburned fuel up to a level high enough that it is too rich to ignite in the pipes. Maybe someone can confirm or dispute this.
Having said that, I also think that waaaay to much emphasis is placed on the supposed detrimental effects of a little decel popping on the bike/motor. I am just not convinced that it causes harm to the engine. There has been a lot of speculation, but nobody here has been able to PROVE that it has caused a failure in their motor.
Having said that, I also think that waaaay to much emphasis is placed on the supposed detrimental effects of a little decel popping on the bike/motor. I am just not convinced that it causes harm to the engine. There has been a lot of speculation, but nobody here has been able to PROVE that it has caused a failure in their motor.
Thread Starter
|
Road Warrior
Joined: Nov 2006
Posts: 1,439
Likes: 2
From: Lancaster, PA
RE: The Great Decel Popping/Backfire Debate
ORIGINAL: Tech2
I may be wrong, but I thought that richening the fuel-air mixture brings the amount of unburned fuel up to a level high enough that it is too rich to ignite in the pipes.
I may be wrong, but I thought that richening the fuel-air mixture brings the amount of unburned fuel up to a level high enough that it is too rich to ignite in the pipes.
Get acup of gas and throw a lit cigarette in it. Nothing will happen except the cig will go out. My bitch is that it's almost a automatic statement that if your getting a pop or backfire you are lean. Bull ****. There are plenty of other variables to consider.
Trending Topics
Cruiser
Joined: Mar 2007
Posts: 126
Likes: 0
From: the Iron Range
RE: The Great Decel Popping/Backfire Debate
mine hasn't popped or backfired since I bought it...should I get a refund from the dealer? I just want to be part of the "in" crowd.
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
7 Surprising Harley-Davidson Products that Are Not Motorcycles
Verdad Gallardo
8 Best Harley-Davidson Motorcycles Ever
Pouria Savadkouei
10 Worst Harley-Davidson Motorcycles Ever
Pouria Savadkouei
Killer Custom's Jail Break Is The Breakout That Refused to Blend In
Verdad Gallardo
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Verdad Gallardo
Harley-Davidson Reveals Super Cool Cafe Racer Concept
Verdad Gallardo
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Verdad Gallardo
10 Motorcycles You Should Never Buy
Joe Kucinski
10 Things Harley-Davidson Needs to Fix in 2026
Verdad Gallardo
Thread Starter
|
Road Warrior
Joined: Nov 2006
Posts: 1,439
Likes: 2
From: Lancaster, PA
RE: The Great Decel Popping/Backfire Debate
ORIGINAL: Tech2
I do think the decel popping is caused by a lean condition. My understanding is that it is caused by unburned fuel (in the exhaust gasses) igniting in the head-pipe. I may be wrong, but I thought that richening the fuel-air mixture brings the amount of unburned fuel up to a level high enough that it is too rich to ignite in the pipes.
I do think the decel popping is caused by a lean condition. My understanding is that it is caused by unburned fuel (in the exhaust gasses) igniting in the head-pipe. I may be wrong, but I thought that richening the fuel-air mixture brings the amount of unburned fuel up to a level high enough that it is too rich to ignite in the pipes.
] then you arelean condition.
Thread Starter
|
Road Warrior
Joined: Nov 2006
Posts: 1,439
Likes: 2
From: Lancaster, PA
RE: The Great Decel Popping/Backfire Debate
ORIGINAL: BaggerSteve
mine hasn't popped or backfired since I bought it...should I get a refund from the dealer? I just want to be part of the "in" crowd.
mine hasn't popped or backfired since I bought it...should I get a refund from the dealer? I just want to be part of the "in" crowd.