| Author |
Message |
    
Bg05xb12r
| | Posted on Wednesday, May 20, 2009 - 10:44 pm: | 
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This has probably been asked a hundred times. (I Kinda looked at archives but gave up easy) I have an 05 XB12R with Race ECM and Jardine exhaust. The damn thing has Popped on deceleration or engine braking since I got it. Any simple solutions? Thanks. |
Kalali
| | Posted on Thursday, May 21, 2009 - 01:42 am: |
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Some decel pop is normal but I would look for intake and exhaust leaks if you think it is too excessive. Decel pop is usually a sign of lean mixture.
There are folks with more expertise here who could correct me if I am wrong. |
Bg05xb12r
| | Posted on Friday, May 22, 2009 - 03:14 pm: |
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Thanks for the info. I will check out the Intake/exhaust for leaks. |
Danielrg_usa
| | Posted on Saturday, May 23, 2009 - 10:26 pm: |
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that is correct. decel pop is caused by a lean mixture. a leak in your intake or exhaust is possible but unless it is excessive it is completely normal. use a propane bottle with a hose as a probe to pump propane in the area around the intake manifold and heads. if the propane gets pulled into the engine it will kill it instantly. you can also use brake or carb cleaner but this is a little more dangerous because it could ignite. the only other safe alternative is to use a spray bottle and saturate the area around the seals with water. if there is no leak found you may just need to tune your ecm. richening the mixture will reduce and or eliminate the problem. |
Id073897
| | Posted on Saturday, May 23, 2009 - 11:53 pm: |
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decel pop is caused by a lean mixture. a leak in your intake or exhaust is possible but unless it is excessive it is completely normal.
Decel is always lean, as fuel is reduced by the ECM. |
Blake
| | Posted on Sunday, May 24, 2009 - 09:41 am: |
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I'd further clarify that decel popping can be caused by a poor seal at header to cylinder head connection(s). This is especially evident in more richly tuned engines, take for instance my race tuned Cyclone (carburetor), or any XBike with the Race ECM. |
Danielrg_usa
| | Posted on Monday, May 25, 2009 - 03:52 am: |
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yes decel pop is always due to a lean mixture. however, on a fuel injected bike it can be eliminated by tuning the ecm with a race tuner. there is an area in the program used to do this. that is considering there are no leaks present in the intake or exhaust. } |
Blake
| | Posted on Monday, May 25, 2009 - 10:59 am: |
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A rich running engine will absolutely exhibit decel popping when it develops air leakage at header to cyl head seals, whereas a lean running engine is less likely to do so. T
Decel popping is due to secondary ignition of fuel vapors inside the exhaust tract. A lean running engine is, once warmed up, unlikely to charge the leaking exhaust tract with fuel. For that to occur, a rich condition is required. The leak at the header to cylinder head seal allows the needed oxygen/air to enter the exhaust tract and ignite, this the popping under decel as unburned fuel exits the combustion chamber along with the still burning rich mixture. As soon as more oxygen is added, "POP, pop, pop, pop" secondary ignition ignites the remaining fuel.
(Message edited by Blake on May 25, 2009) |
Id073897
| | Posted on Monday, May 25, 2009 - 04:01 pm: |
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My XB9 is running lean in decel and is popping like hell then. The explanation is, as the mixture is too lean to fully burn, unburnt gas will get collected in the exhaust. As this is a lean condition, more than enough oxygen will be present. |
Blake
| | Posted on Tuesday, May 26, 2009 - 11:48 am: |
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If the mixture is too lean to burn in the combustion chamber, how would it ignite in the exhaust tract? |
Id073897
| | Posted on Tuesday, May 26, 2009 - 12:23 pm: |
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By other means than a spark. Hot gas, free radicals, glowing debris, whatever. It might even start burning in the combustion chamber, but the flamefront comes to a stop before consuming all fuel, leaving enough HC to accumulate in the exhaust. |
Blake
| | Posted on Wednesday, May 27, 2009 - 05:25 pm: |
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Fuel left over in a lean mixture? It's difficult to see how that could happen. I just know that when I've seen exhaust popping under deceleration, its always been on bikes that were running rich, some with exhaust leaks at the cylinder head to header connection; they weren't necessarily too rich, but they were not running lean.
I've seen lean running carbureted bikes cough and poot out the intake due to misfires and reversion of intake charge. That was common on the carbureted tube framed Buells until one increased the low speed jet size and adjusted the idle air mixture screw to enrich the mixture. |
Bombardier
| | Posted on Thursday, May 28, 2009 - 08:41 am: |
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Reversion may well be the culprit as the Jardine has a shorter direct length from header to exhaust outlet. |
Id073897
| | Posted on Thursday, May 28, 2009 - 09:36 am: |
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Fuel left over in a lean mixture? It's difficult to see how that could happen
No, in contrary, this is a very common situation, easily to watch with a 4-gas tester.
As written, the flame comes to an early stop because it's not even but frayed and so is the shockwave running in front of it. This is one of the reasons why pistons overheat under load and lean conditions, as the flame follows rich spots, creating more turbulence, hence driving burnable gas deep down to the piston head, which under good conditions is screend by a layer of (mostly) air or exhaust gas. |
Brandon_m
| | Posted on Tuesday, June 02, 2009 - 12:00 pm: |
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Also keep in mind the Jardine will pop on decel naturally. It's just one of the things it does. American Sportbike came across this in their exhaust tests and Jardine also said the same thing. But hey, checking out everything mentioned above won't hurt either. |
Kmfw160
| | Posted on Tuesday, June 02, 2009 - 01:34 pm: |
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I've had that problem before and it turned out to be a loose spark plug. |
Xb9sbear
| | Posted on Tuesday, June 02, 2009 - 06:07 pm: |
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Don't forget that altitude can play a part as well.
A factory Race ECM may need to be fine tuned different up in CO, as opposed to down here in TX...
No? |
Acityxj
| | Posted on Tuesday, June 30, 2009 - 12:02 am: |
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decel popping is not a bad thing. from my understanding it's just unburnt fuel that is ignited by the hot exhaust left inside the exhaust port. You just can't hear it with a stock exhaust because of all the chambers it has to flow throw instead of just straight through like all of the aftermarket exhaust. I read on a thread that the efi systems do this as a type of cooling for the cylinder head. that's my 2cents, correct me if I'm wrong? |
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