| Author | Message | ||
     Streetfightercityx |
Is this a normal occurrence with upgraded pipes? Does decel popping pose any threat to the longevity of my engine (valves?)? Thanks in advance! Brent | ||
| Daves |
did you change the ecm or just throw a pipe on it? Which pipe? It usually means you have a lean condition that over time can cause engine damage. | ||
| Pwnzor |
OK somebody give the whole story on this please. I've been told the popping is normal... I have the factory race kit. It's popped like that since it was installed. Daves, you say "usually" means a lean condition. Does that mean "sometimes" its not lean? What kind of engine damage are we talkin bout here, in non-techincian terms if possible please.  | ||
| Henrik |
On my old S2 popping on decel is usually a sign of one of 2 things: 1) I didn't install the pipe correctly and have an exhaust leak somewhere. Often at the heads. 2) header has cracked where the 2 joins into 1. Now don't freak out. You're not riding a tuber, but you could still have an exhaust leak somewhere if you've been messing with things. Henrik | ||
| Daves |
That is why I asked what pipe and if he changed ecms. Some popping is pretty normal but I haven't seen or heard his bike Hard to tell over the net  | ||
| Barker |
Mine pops too!  Only when I lay off the gas in low gears. I am 300 lbs. I always thought it was the large amount of inertia on the engine braking. It that bad? Race ECM/pipe installed at dealer. What is a lot or normal/abnormal popping? (Message edited by barker on June 08, 2006) | ||
| Chadhargis |
Mine does it when my bike is cold. After it warms up, she purrs like a kitten. It doesn't really pop per se, more like a "burrble". Race muffler and ECM self installed. I did, however, seal the junction where the header connects with the muffler with high temp copper silicone. An air leak can cause popping from what I've been told. | ||
| Streetfightercityx |
I have a Race ECM (with TPS reset). I have a modified stock pipe. This means that the top of the pipe is opened up, one of the baffles is disabled and the top of the pipe is closed again. I'm in the middle of getting prices quotes from Daves (I'm the same Brent sending you emails on pipes) and then I read the Exhaust shootout report. I can still get a Buell Race Pipe (a dealer here can still get their hands on a few - I don't know how) but I was leaning towards the Jardin but Al states in his summary of the Jardin that "It tended to have more decel popping than most of the other pipes." This tells me two things: 1. Other pipes pop on decel. 2. Jardin does it more than the rest. My current pipe pops and I'm looking to stop that. So, I'm not thinking the Jardin is my best option. But if ALL pipes pop, then I'll stick with what I have. Thoughts? | ||
| Barker |
Chad, Now that I think about it, The bike only "pops" when cold. My old M2 with the D&D full system popped really LOUD all the time! I think I had it all sealed up. | ||
| Josh_cox |
The popping is generally a sign of running lean on decelleration. When we tune bikes, normally we will dump X% fuel extra at redline-1500 rpm at 0% throttle. This will keep the bike from running so lean when decelerating. It can also create a nice flame when you shift if you let off sometimes  The race ecm isn't bad, but it isn't perfect either. Josh | ||
| Elff |
Happens on mine with a Race Kit. I call it the Rice Krispies  | ||
| Buelltroll |
My D&D pops pretty bad all the time(n it annoys the s*** outta me) When the bike warms up it gets worse. If I'm riding hard and the bike gets HOT it gets so bad it'll pop just upshifting.  Has been tested by me and a dealer for leaks too. (Message edited by buelltroll on June 08, 2006) | ||
| Dmextreme |
race ecm - tps reset Odie Pipe K&N Filter Decel Pop. all the time. warm or cold. Didn't do that on the stock set up, and not to mention it is sealed up damn good too. I don't know what to do. Kinda more worried about getting my Gixxer 750 going, still waiting for them to get the tranny fixed.. then I am going to paint saphire blue. Sigh.. time.. time.. time.. Top it off.. wife is leaving.. good friend just passed riding.. its been a horrible horrible month of June.. G/L guys/gals.. Be safe.. wear your gear.. | ||
| Beachbuell |
04XB12R with a factory race-kit. Pipe, filter, race ecm and it pops on hard decel. This is a pretty normal thing, I've had the same thing happen on other bikes I've owned (cruisers and sportbikes), they all popped on decel after putting a pipe on. As far as the bike running lean or rich........... I dynoed it the other day and the air/fuel mixture is dead on. I say just ride it. | ||
| 984gasm |
Mine also, noticed more lately! I have drummer pipe, race ecm, and buell race filter. How do you tell if it is infact a leak, because I have a feeling that is what it might be. | ||
| Rafartist |
Its not leaking, the aftermarket pipes are able to scavenge alot more air and have no baffles to deaden the sound. If you take notice, it usually happens right around 3k, Al told me its a transition spot in the computer where it goes lean because the throttle is shut and isn't reading any voltage to keep dumping fuel. I think thats what he meant  | ||
| Kdan |
Mines stock, except for the open airbox and when riding spiritedly, it pops on deceleration. All the time. I think it's cool. | ||
| Cycleaddict |
my 9/s pops on high rpm decel. but i can stop the popping (if i want to) by slightly cracking the throttle open !! | ||
| Rafartist |
Yeah wait till you hear it some time coming from a Jardine, it doesn't sound so cool, mines obnoxious. I feel like one of those kids with a fart can hanging off the back of their "race car". | ||
| Vaneo1 |
POPPING IS NORMAL PEOPLE!!! ITS a V-TWIN | ||
| Bads1 |
I got a 9S with a race kit....no pop!!! I got a 12S with a D&D on it.... no pop...go figure?? | ||
| U4euh |
sorry to hear that DM, keep your head up. back to the thread. | ||
| Silverado140 |
Not only is it normal, but it's WAY COOL!!! It's half the reason I installed the race kit on my 9. | ||
| Firebolteric_ma |
i run a jardine w/ F.A.S.T kit and it popped all the time till i added the direct link software to my bike.(map for open airbox/jardine) popping is almost all gone, once in a while(maybe due to not a "perfect" match w/ D.L) i hear it but that's about it. D.L helped stop popping quite a bit. my bike was running super lean till that point.(hence the popping all the time) | ||
| Hogs |
I always thought popping/backfire was a sign of rich out the exhaust sometimes??? Coughing out the intake sign of LEan...? | ||
| Pwnzor |
I enjoy causing whiplash in bystanders, but if its really a sign of running too lean I'll have to address the issue I suppose. Good thing the bike is loud whether it pops or not. | ||
| Luckydevil |
Hogs, You are right. ignition of spent gasoline on hard deceleration is a sign of a temporary rich condition. too much fuel. add a little air (open throttle) will help quiet it. If it were a lean condition, what could be burning to cause the pop? | ||
| Hogs |
Atleast that is with Carb. bikes, But not sure with FI, Could be a whole different can of worms.?? | ||
| Xb9 |
XB9 Stock ECM mapped w/DL Drummer FAST Mine popped before I mapped it with a wideband controller and DL -non after. | ||
| Josh_cox |
If it was rich you would see black smoke, then a pop with a flame. What you guys are talking about is from being too lean. We ran a few different customer XBs when they complained about the popping after getting race kits or other slip ons. They all ran around 15.5:1-16:1 on deceleration and around 15:1 on a light cruise. Being that lean on an air cooled twin isn't good. Around 13.2:1-13.7:1 usually makes the best power and still keeps the engine cool. The direct-link setup is the way to go right now for sure. About all vtwins popping. This is not true. With a properly tuned engine/pipe setup it should not pop much if at all, unless you are running a straight pipe. Then, there isn't much that can be done except to tune it safely and let it roar. Josh | ||
| Al_lighton |
Here is some info that may help with deciphering it all. Decel popping is fuel igniting in the exhaust system. I think everyone has that part figured out. But how and why it gets there, and why it ignites there, is the issue. When you chop throttle at 6000 RPM, your throttle position goes to the idle position, or perhaps just above it, depending upon your riding style. If you looked at your fuel map, you would find that the 5% and 7% throttle position, 6000, 5000, 4000 RPM fuel cells would have a very low number in them. But not Zero. For instance, in the Buell fuel maps, the value is a 40 (255 is the max value, and values in the 200's are common in the high throttle part of the map). The reason for this is that this condition can ONLY occur when you chop throttle from a high RPM. 5% throttle, 6000 RPM is impossible to achieve any other way, it is ALWAYS a decel condition. By scaling the fuel WAY back, the air/fuel ratio is not one that can support complete combustion in the cumbustion chamber. If you chop the throttle on the dyno with the O2 sniffer hooked up, the mixture goes off the charts lean Those fuel values exist mostly to control popping. Why isn't it Zero? Because the little bit of fuel squirted in is for cooling. But that fuel that doesn't combust in the chamber moves into the pipe. If enough of it collects there, and hits enough O2 and a hot spot to ignite it, BANG!!! It pops. But there isn't much left for collecting in the muffler due to the values in the tables. But if you ride an XB, you'll note that you don't have a popping problem above 4000 RPM. It just isn't an issue. But the reason it becomes an issue below 3000 RPM is because the fuel tables in the 3000 RPM and below for the 5,7,and 11% throttle position columns don't have a mere 40 value in them. They have more fuel, because the engine moves into a region where the fuel tables represent real world operable conditions in steady state non-decel operation. So more fuel is being dumped into the exhaust system, and larger combustible mixtures can be formed there. The Buell XB ECM has a way to deal with this. It knows when it is in a decel hysteresis condition, and when it detects this, it applies a huge fuel cut on the fuel map values. With Directlink, we can control which throttle position vs RPM that this big fuel cut occurs in to modify and control popping. The tube frame ECM doesn't have a controllable decel table, however. But the ECM also has a temperature override. If the temperature is above a certain set point, that fuel cut doesn't occur. By not cutting the fuel, more engine cooling is obtained, but more popping occurs as well. I suspect that this MAY have something to do with the reason why race ECMs hang at idle when they are hot, but I don't know this for sure. It may be a timing issue instead, I'm not sure. Popping is hard on glass-packs, but doesn't hurt other mufflers. It isn't like the carbureted bikes where you could coast downhill with the kill switch off, then turn it on and shoot a 5 foot flame out the rear (big fun, but I've blown up mufflers this way!). The explosions aren't that big. There are two ways to reduce popping. One is by smothering it in fuel, the other is by starving it from fuel. Smothering can work but also can lead to bigger pops, and it also has cooling benefits. Starving makes for smaller pops and less cooling. Seems to me that the Buell ECM is set up to starve for controlling popping. It saves more fuel, reduces emissions, and the Buell pipes can take it without any issues. As others have indicated, O2 leaks in the system can lead to popping, because they can take a condition that wouldn't normally result in a combustible mixture, and give it enough air to become one. Free flowing pipes are more prone to popping because reversion effects are more pronounced, and more O2 from the exhaust exit can be brought forward into the muffler "combustion chamber" where the O2 and Fuel can encounter an ignition source. Some popping with free flowing pipes IS a fact of life, I'm afraid. It doesn't bother me at all, but it is hard on a Jardine muffler, for instance. Carbureted bikes aren't quite the same, the fuel that they get is dictated by the airflow through the carb, not a map. FI bikes deliver the same fuel at a given throttle position/RPM regardless of airflow. Al | ||
| Kurosawa |
OK now you mentioned it being hard on glasspacks. In several of the muffler descriptions, you said some were non-replaceable glass packed but appeared to be designed not to need maintenance. Do you mean they're not all that bad with the glass burned out, or do you mean for some reason the glass will last an unusually long time, even given burnoff of fuel in the exhaust tract on decel? | ||
| Bake |
Good reading Al, thanks!! | ||
| Luckydevil |
Thanks Al. (this is for my benefit, i want to be sure i have it right.) The map dumps a little too much fuel to combust upon decel because the 5% 7% and 11% have a value higher than optimal for the engine speed/throttle posititon combination. This is done to correct for the lean condition that normally occurs. However the ECM will detect a decel hysteresis condition (too much fuel?) and cut the fuel map and lean it out, unless you engine is above a certain tempurature in which case it just lets the thing overfuel to cool. So does this mean that the ECM is creating an overly rich compensation for a naturally lean occurence? I am at 5000+ feet and evey buell i have heard up here pops on hard decel. And i can think of about six other bikes that produce a visibly darkened exhaust on a hard decel too. New/old doesn't matter. Course everything up here has to work not to be too rich anyway. Edit: So, the answer to the original thread question is... (yes?) this is normal for a buell to do??? (Message edited by luckydevil on June 12, 2006) | ||
| Al_lighton |
I think you misunderstood. The fueling in the 5/7/11% throttle positions aren't optimized for decel, they are optimized for running the bike from 800-2500 RPM in non-decel events. So when decel occurs across those throttle position/RPM points, they are putting in more fuel than you need during decel. Above 3000 for those throttle positions isn't an operable condition so the fueling values there are ONLY for controlling decel popping. Those rich values aren't there "to correct for the lean condition that normally occurs", they are there because it is a normal operation point during non-decel. And that's why there is a decel table to modify those fuel values during a decel event to minimize popping. At altitude, the AFV should be compensating the fuel values by lowering them. The accel and decel functions are in addition to the AFV fueling modifiers. It is somewhat normal for there to be some popping with free flowing pipes due to reversion effects that allow O2 to come back into the muffler "combustion chamber" and form a combustible mixture. If the combustible mixture happens outside the pipe, there is rarely a spark or hot spot to trigger combustion. But inside the muffler, there easily could be. And even if it did occur at the exit to the pipe, it wouldn't make much of a pop, because the explosion isn't contained. Take a firecracker, pour the guts on the ground, and light it, and it just goes fzzzzzz. Contain it, and it goes bang. Same thing happens with gasoline ignition. That's why an leak in the exhaust system can make for big popping, as it provides O2 to help make combustible mixtures up in the pipe, not at the exit. You can effect the popping or not by not slamming the throttle completely shut and leaving it there. If you're getting popping at any RPM, change your throttle position slightly and there is a good chance you'll make the popping go away. You're changing the fuel mixture in the process from one that supports muffler combustion to one that doesn't. As flammable as gasoline is, it still has to be at the right mixture in order to combust. Al | ||
| Luckydevil |
Thanks Al, I think i get it, but i also think phrased it wrong. The map below 3000rpm isn't intentional compensation, but operational for those throttle positions+RMPs, got it. It read to me like there is a decel table for the 4000 and up, but not for 3000 and below. Is the "decel table" you refer to the same as the "fuel cut" described in you first response? It did not read to me like the same thing, but it may be. About altitude... I was thinking the altitude (which can get to 10,000 feet on a saturday ride ) can really push the limits of the AFV ability to compensate for thin air. I know the O2 sensor feedback loop can adjust, but if the decel condition is already going rich below 3000 RPM, will it be exaggerated with an increase in altitude? The fact that air just does not cool engines well at high altitude means that we do run engines hotter. Higher than average engine temps may prevent the ECM from cutting the fuel map as you mentioned. Or does the AFV have a much broader ability to compensate than this? If the AFV does have broader optimizational abilities than i expected, does this put to bed other peoples claims that adding a hi-po muffler (not an air filter and ecm swap/re-map) you will put your Buell into a potentially engine damaging lean condition? Thank so much for stepping up with a lot of first hand knowledge. And taking the time to field the questions of those who want to learn more about their bikes. rob (Message edited by luckydevil on June 13, 2006) | ||
| Luckydevil |
Al, just read through your very comprehensive exhaust shootout, and it answered my question. but raise another. I will post it separately. thanks | ||
| Hammeroid |
Before I read this thread I thought that the popping was normal and I kind of liked it. "American V-Twin, Hell Yeah." But now I am not sure. I have factory race kit on my Ss. Should I ask the dealership to check out the popping when I bring it in for its 1k check-up, or would I be trying to fix something that's not broken?????????? Thanks for any help in advance. |
