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2014 FZ09 w/ 13,500mi
Akra Carbon
Vcyclenuts flash
Flash and exhaust have been on the bike for approx 4,000 miles.

One ride I noticed that it was popping a bit on decel. If I ran through a gear hard and cut the throttle it would occasionally backfire.

Seemed to do it mostly in the midrange (5-8k)

Ran like that for around 300 miles and just last night I noticed it wasn't doing it at all. Completely back to normal??


When it was acting up, everything else felt fine. Full power, started right up, idle was good.


I checked for an obvious exhaust leak, but header bolts were fine and muffler was secure.

It started in the middle of a tank of gas, and ended in the middle....with about 3 tanks through it.


I'm not sure what to think of it. Fuel filter perhaps?
 

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What you are experiencing is likely 100% normal.

The difference may be ambient temps, and how hard you are romping on it, like you said.

When that exhaust gets really hot, any unburned fuel that touches it will detonate in it. If you were romping on it, and immediately closed the throttle, it would cut ignition and any residual unburned gas in the cylinders would sent through the hot exhaust.
 

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AIS is disabled with that flash, right?
 
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Hope it's not a burnt valve.
 

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Mine will do that also..when coming down from a hard run if I shut the throttle off all the way then feed just a bit it will do it ...normal Just ride the thing ...mine has the SC full header ,Vcyclenut flash,AIS blocked off and with a EJK controller.. As stated in post #2 normal . If you ever watch the Moto America races and superbike and Moto GP most of them do the same thing at the RPM's ranges you have stated !
 

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One ride I noticed that it was popping a bit on decel. If I ran through a gear hard and cut the throttle it would occasionally backfire.
Occasionally is not something to worry about. It has to be there every time. Phantom pops can be TPS to RPM input against the IAP (I am pop) because this be 'pressure in is pressure out.' But for it to clear up?

Seemed to do it mostly in the midrange (5-8k)
Sounds more like a 'learn' process, but this bike has no relay off the ECU. For it to clean up is either weather or? I'm stumped.

When it was acting up, everything else felt fine. Full power, started right up, idle was good.
What Annihilator said, and I'm mentioning about how many days/weeks between rides, and night sure sounds rich with lots of molecules tightened up in the ambient.

with about 3 tanks through it.
Same gas station I'll guess and that's more of a mix of old and new [if a delivery came in between] and you ran a bad round thru it, but cleared up somehow half tank?... can't see being gas.


Fuel filter perhaps?
Fuel filter does not clear up at a half a tank, right?


LouG, that's more where I was going. Where are the reed valves (if apply) in all this? Carbon holding a blade open until it blows/burns off? If no AIS in play, then move on to the next guess at it.
 

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Mine will do that also..when coming down from a hard run if I shut the throttle off all the way then feed just a bit it will do it ...normal Just ride the thing ...mine has the SC full header ,Vcyclenut flash,AIS blocked off and with a EJK controller.. As stated in post #2 normal . If you ever watch the Moto America races and superbike and Moto GP most of them do the same thing at the RPM's ranges you have stated !
It's not even just motrcycles. It's all fuel injected motors. And they will do it 100% stock, it's just harder to hear it with a quiet exhaust.

It's probably more exaggerated on the FZ09 because you train yourself to never close the throttle in account of the snatchy on/off, so you leave it slightly cracked at all times.
 

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abe, an OP says it: 'idles, runs fine otherwise.' A member posts that it might be a burnt valve. Burnt/bent means 0 compression if not bumps the needle to 20 psi or less is the giveaway. Show me how confused you are if I said it can't be a valve if the OP calls the idle, let alone it starting and running. Are the 3-amigos in play? I believe so if there is spark to light the gas. All that is left is the kinetic.

No start means something on the list is out of the loop:
Fuel
Spark
Compression = Oh look it starts!

Wasn't that enough of a clue to tell it's not a burnt valve? Ever so burnt and the pop is constant, and will not go away after 300 miles. Make sense yet? Isn't it more a fuel issue rather than comp or ign?

Comprehension of engine theory is what might be confusing you. You have to prove that recognizing compression [starts, runs, etc.] an me confusing you that someone suggesting a valve, and [you] NOT recognizing the bike runs = Not the valves per say. Confusion has no logic to it. Take the valve as a possibility. Way too many variables at the valve like burnt/bent/tight. It's pointless to explain how simple this valve suggestion was not thought out. It did not confuse me as I reached into my mental toolbox and ask which amigo has left the casa? They are all present, correct?

Still confused seeing the common sense side of it?
 

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The AIS when disabled can leak. It did on my 2015 FZ. I had to use block off plates for the pooping to stop. I have the vcyclenut flash and he disabled the AIS. It may prove wise to drop $35 and put on the block off plates to narrow that down.

Explanation - The rubber stopper that closes off the air when the AIS is disabled can dry out a bit, if this happens, air leakage can occur, it did on mine. Block off plates solved my problem. My 2 cents.
 

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Dry rubber stoppers do not leak and seal up after 300 miles. That's the clue.... Rubber 'clears up' is to think this one out. Are we on the same page yet or stuck on abe's beezwax page?

You do understand the OP's mileage window, correct? Everyone has a good call, but not for 'clears up after 300 miles.'
 

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Dry rubber stoppers do not leak and seal up after 300 miles. That's the clue.... Rubber 'clears up' is to think this one out. Are we on the same page yet or stuck on abe's beezwax page?

You do understand the OP's mileage window, correct? Everyone has a good call, but not for 'clears up after 300 miles.'
Hey look I did not say anything about burnt valves ! Just a mixture of gases igniting when going on and off throttle....
 

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abe, think it out... 'on and off throttle' is a given when riding. But at the end of the day, on/off is still happening... where is this in the 300 mile window of no more pop?

Annihilator: ambient change.. Big weather change between tank fills. So the OP has to answer... Last tank full was 3 months ago/3 weeks ago/within 3 days so the ambient can be used or thrown out with the burnt valve = Pop or not.
LouG: AIS in play [or not?] says; a carboned up reed valve stuck open/burned off =no more pop.

Again, the OP is nowhere to be found to clear these two variables.
1. Yes/no there was a lag time between tank fills.
2. Yes/no there is/not an AIS in play.

Between all the call-outs, I'm clueless to the 'popage vs. mileage,' and between all the head butting I thought how these two variables would narrow it down rather than throwing darts at it like a valve and normal on/off throttle [no matter the rpm range] the moment you leave idle.

See it yet we keep clearing up the confusion?
 

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2014 FZ09 w/ 13,500mi
Akra Carbon
Vcyclenuts flash
Flash and exhaust have been on the bike for approx 4,000 miles.

One ride I noticed that it was popping a bit on decel. If I ran through a gear hard and cut the throttle it would occasionally backfire.

Seemed to do it mostly in the midrange (5-8k)

Ran like that for around 300 miles and just last night I noticed it wasn't doing it at all. Completely back to normal??


When it was acting up, everything else felt fine. Full power, started right up, idle was good.


I checked for an obvious exhaust leak, but header bolts were fine and muffler was secure.

It started in the middle of a tank of gas, and ended in the middle....with about 3 tanks through it.


I'm not sure what to think of it. Fuel filter perhaps?
OP, where the majority of those 300 miles short trips, before the engine was warm, or would you say longer than 8 - 10 miles each?

Did it clear up, or has it reoccurred? Just trying to see if you have fixed the issue?
 

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Catch22 is here to confuse you ...do not pay attention to any of his posts...they do not make sense...
Abe, for your honest post, you have won the FZ09org forum award. This is a one-time award, non-transferable, and must be used within one year. Your award is an all-expense lunch with Catch22...restaurant of your choice. Enjoy!
 

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Abe, for your honest post, you have won the FZ09org forum award. This is a one-time award, non-transferable, and must be used within one year. You award is an all-expense lunch with Catch22...restaurant of your choice. Enjoy!
Spacecoast, is the voucher good for alcohol? I am sure Abe will go if it does, am I correct Abe?
 
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