A Little popping is normal it was there when you had stock pipes and mufflers on. Now that your pipes are more open you will hear more. But if it is back fires and a whole lot of popping then ad a little more fuel to your decel mode.

 

Well, I have never seen a rich condition causing popping out of the exhaust. If it's coming out of your throttle body (or carb) that is a rich condition. Out of the exhaust is a lean condition, typical of modern Harleys compliments of the EPA.

I am not familiar with the model Fueler that you have but if it's what I think it is, then you won't need a dyno... there isn't enough adjustability to make it worth the expense. You can modify the air/fuel ratio enough to solve the popping on decel.. it will just lower your gas mileage some.

C#

 

Popping on deceleration can occur in the exhaust if there is unburned fuel (too rich) coming in contact with air coming in through the mufflers. It's more pronounced with the bigger mufflers because of increased volume. On deceleration, exhaust isn't being "pushed out" as it is in acceleration, so the vacuum created on deceleration allows air to come in and, if there's unburned fuel in the exhaust, it'll ignite. As everyone else said, exhaust leaks are also an area to check.

 

My Take, (sorry, but very opinionated)

If it's popping then it's rich on a decel circuit. Like Misbehavin said, the popping was there right off the showroom floor. When I first took my bike off the floor with stock exhaust, I could hear a ton of popping on decel, it was just muffled. All I could think was 'This is gonna sound great with more open pipes.' And it does. I guess I'm he oddball but I like the noise. The pipes are only loud when I'm on it, otherwise it's just a low freq rumble so overall I think I'm on the lower end of the annoyance scale.

I also noticed that if I just let off the throttle on decel and leave it alone, there is no pop. If I feed it just a little throttle then let off, It will start to pop. I must be going to another circuit when I momentarily call for fuel on decel.

I'm not interested in more performance myself, if I was I'd have a crotch rocket. This 103 pulls hard and I don't want to mess with it too much, even the 96 CI was fine for me, though I like the sound and behavior of the american exhaust pipes. I'm not going to go on a rant about displacement and marketing.

I understand it's just a lot of preference, but I try to keep it as simple as possible. Until I see some convincing evidence that the popping is detrimental, I won't worry about it. I've searched quite a bit, but haven't found anything to make me think otherwise. On the other hand, If I didn't like the noise I bet I'd be trying to get rid of it real quick

Joe

 

Although a little popping won't hurt a thing some don't like it..

I just spent almost 1/2 hr reading about HD popping on Decell.

Every article I read by someone who should know said Its a Lean issue.

So IMO I'd try that way 1ST if worse then go the other way.

As said before, a litttle won't hurt,.

All this said is if Ur head gaskets and muffflers are 100% sealed, as both/one of them will cause same popping issue.



.

 

On my Thundermax I added a little fuel and took out a little timing and it was gone.

 

Popping on decel out of the exhaust pipes is a lean issue. Have never seen anyone of any authority say otherwise. Know from personal experience that richening a Power Commander kills the decel pop (and some power). It's always possible that anything is possible, but the general rule of thumb is lean.

C#

 

thank for all the advice. What i'm getting is a pop or two when crusing around 3000 to 3500 rpm and get out of the throddle quickle. if i easy off the throddle i dom' hear it. I'm running a 2 into 1 pipe with a Arlen Ness big sucker. so i think it would make sense with it being lean.
fuel ann power i not an issuei i bought the pipes bbecause the sound and looks of them. and really can live with the popping ads long ans i'm not hurting ti moted 98 v twin.,

 

Maybe if someone could just explain how too much air and not enough fuel in the front end (lean condition, all fuel is burnt) causes the popping on the back end, it would help educate me and maybe others, because this seems to be an ongoing debate and it seems odd that there isn't agreement on something like that. Everything I find on searching points to unburned fuel or gasses entering the exhaust and mixing with enough air coming in through the muffler or through a leak to cause ignition. My simple search took me to Dodge Racing, Ducati FAQ page on their website, Porsche, and a few others. I'm not a mechanic, but would love to know the true answer to this.

For what it's worth, here's what I think and I think we're all saying the same thing....possibly. Not all of the fuel is being burned inside the chamber and some is getting into the exhaust, mixing with enough air, and is being burned there as well. The "lean" condition is not on the front end, but is in the back end, i.e., mixing too much air with just a little bit of exhaust fuel and gasses to cause the explosion. If the air/fuel ratio is richened, the popping should reduce or stop. Lean in the back end, not in the front end.

 

Again, for what 't worth, so don't shoot the messenger !

From HMF Engineering......

Deceleration Backfire is caused by fuel burning in the exhaust manifold or header.

No ifs ands or buts, that’s what causes it. But the bigger question is how does gas get there in the first place, and that’s a bit more complicated. Generally, there are a variety of ways it gets there, and a variety of things that can make the backfiring worse. But there’s a kicker, and something you should understand before we go any farther:

A motor in perfect tune will exhibit deceleration backfiring.

Therefore, just because your motor is banging it up, doesn’t mean there’s anything wrong. And consequently:

Getting rid of the noise means de-tuning your motor.

Yup. If you’ve just got to eliminate that popping, you’ll have to accept the fact that your motor is going to be forced to run rich to do it, and that isn’t necessarily a good thing. So lets talk about what causes the problem.

Ok, so you’re riding along at some given rpm, and suddenly you decide to decelerate, and you reduce the amount of throttle. This causes an “overrun” – that is, the motors rpm is faster than the fuel provided can support, so the motor begins to spool down. This causes a couple of things to happen.

First, when you close the throttle, you are also closing the throttle plates. This reduces the air and fuel flowing into the motor, and increases the vacuum (lowers the pressure). This results in less air and fuel in the cylinder during the power stroke, which in turn results in a lower pressure in the combustion chamber. Remember I said earlier, that the A/F mix burns faster in proportion to the pressure applied? Well, when we reduce pressure this way, the mix burns slower. This results in two things happening.

1. The lower burning fuel generates less heat, and the cooling effect of the non-burning fuel tends to “quench” the flame front, or slow it down even further. Because the mix is burning much slower, the exhaust valve can open before all the fuel is consumed, and the unburnt fuel is ejected into the exhaust.
2. The engine designers, in order to promote smoother idling and better combustion, retard the spark when the throttle is shut, and this results in the mix being lit later.

So, now we end up with unburnt fuel in the exhaust, and burning fuel being ejected into the exhaust, and bang! Backfire. In addition, Honda has added a device called a “programmed air injection valve” (Pair Valve) that actually injects some fresh air into the exhaust to help this process along – since fully burning the fuel results in cleaner exhaust. So the backfiring is not only a normal part of the engines operation, it’s also intentionally amplified by Honda! Of course, normally, that massive bazooka pipe Honda hangs on your bike hides most of the noise, but it’s there, even when you can’t hear it.

So the bottom line, is: That backfiring is perfectly normal and expected. If you’ve just got get rid of it, that’s up to you. You’re entitled to set your motor up the way you want, and your goals are your goals. But don’t refer to it as “fixing” the popping. Rather, the correct way to think of it is “de-tuning a bit to get rid of the popping”.