F800GS deceleration backfire/rumble?

Discussion in 'Parallel Universe' started by Effisland, Feb 11, 2010.

  1. Effisland

    Effisland No shooting children or pets for next 5 kms

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    Hey guys, I've had my bike for about a week now, and I've been hearing this backfire sound or a rumble sound coming out the back of my tailpipe. Sounds like my old CX650 when I adjusted the carbs too lean - no big bangs though.

    Anyone else get this? My dealer says all the F800s do this. Could this be a problem? I thought it was bad for an engine to do this. But it does sound mean and nasty. Besides that, this engine rocks!
    #1
  2. klarue

    klarue Been here awhile

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    :huh errrr... my 2009 doesn't do that (with an Akro exhaust).
    #2
  3. The Griz

    The Griz Long timer

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    I don't know what you mean by 'rumble' but mine pops every once in a while upon heavy deceleration/engine braking. It's normal for a pop here and there. These bikes have very lean fuel mapping in order to keep the fuel mileage up and emissions down.
    #3
  4. raider

    raider Big red dog

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    Mine does it (Akro pipe, with or without the baffle). So did the demonstrator I rode. It's normal for the ultra-lean mixtures they run these days to pass emissions regulations. Factory pipes usually have enough baffling in them to mask the noise (but not always - my dad has a new Bonneville and it does it too, with stock pipes).

    If you're getting a loud and distinct backfire, like a gunshot, that's bad. If it does it under steady throttle, or acceleration, that's bad. But on downshifts, it's normal for a crackling/popping noise to be present.
    #4
  5. YeeHaa

    YeeHaa Fang it!!!!

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    Yeah mine does it too, so did my ex F650GS for that matter...
    #5
  6. Chop Chop

    Chop Chop Hector erector

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    I get this every time I slow down and change down through the gears. After market pipe though. I actually quite like the pops as I slow down it sounds a bit meaner. Didn't notice it so much with the stock pipe.
    #6
  7. Sydney Rider

    Sydney Rider Been here awhile

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    I get it all the time.... and personally I really like the sound (and if you practice you can make it happen on demand).

    Funny enough when people, but generally not other riders, talk to me about the F800GS they comment on the burble/rumble saying that they think its cool.

    Tony
    #7
  8. capt_enduro

    capt_enduro tool whore

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    Somewhat of a 205, as this has been covered before. General consensus is that just about all the F8's do this and most folks like it (the pop-pop-pop on deceleration).

    Mine does it quite a bit sometimes and not others, and not exactly sure why. I'm working with a theory that it has something to do with the amount of ethanol in the fuel at any given time - not tested it though.


    :D
    #8
  9. itsatdm

    itsatdm Long timer

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    Yes they all do that, though I am not sure about the rumble part. If it was me I would contact the dealer to make sure the latest "map" was installed. A week ago my broken speedo and fuel related gauges were fixed with an updated map and a side benefit was the lessening of the BMW backfire noise, along with what seems like better off idle throttle response. I wish I could tell you what the mapware fixed but it must be a trade secret or at least my dealer did not know. As to the rumble noise, unless you are sure it is exhaust noise, I would pull the rear wheel and make sure the bearings are ok.
    #9
  10. Bayner

    Bayner Long timer

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    I have an aftermarket exhaust also. Regardless, I have found that if you give it very slight throttle while decelerating, rather than fully closing the throttle, the popping is produced every time. Sometimes it's fun, and at least I know how to avoid it if I'm riding where it's not appropriate.
    #10
  11. rdasilva

    rdasilva Adventurer

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    I've got a Leo Vince exhaust pipe and it backfires on deceleration. It happens mostly in second gear. It popped a lot more when I first got it and now seems to have mellowed out a bit. Either that or I've gotten more used to it. I'll have to try the slight throttle versus full off on deceleration and see what happens. It would be nice to have it pop or not on demand.
    #11
  12. EnderTheX

    EnderTheX Dirt Rider

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    I've noticed mine does it reliably any time the engine is cold and only sometimes when it is hot. Definitely not a bad thing!
    #12
  13. klarue

    klarue Been here awhile

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    Well... yeah, I guess mine DOES pop every now and then in contrast to my previous report.
    #13
  14. RicH2

    RicH2 Ric H2

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    Is there no aftermarket remapping ?
    #14
  15. mountain36

    mountain36 Been here awhile

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    Mine did that today, twice. The sound was so loud, really like a gunshot. It what this is suppose to be bad?
    #15
  16. Trout

    Trout Been here awhile

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    Yes.
    #16
  17. ride2little

    ride2little Riding Like the Wind

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    Power Commander is one option.
    See here.
    #17
  18. JoelWisman

    JoelWisman Long timer

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    unless you have a really loud non oe exhaust, loud like a gun shot is not normal.

    If you retrofitted a loud non oe exhaust then 1: you seriously screwed with your back pressure, lost low end torque, and screwed up your fuel mixture and 2: apparently like noise so hopfully you are enjoying the backfire too :)

    Stock exhaust? Loud like a gun shot means something is wrong.
    #18
  19. Dave92029

    Dave92029 Been here awhile

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    Every so often mine does that...so what's the problem? :huh
    #19
  20. JoelWisman

    JoelWisman Long timer

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    Loud, like a gun shot?

    If it's truly that loud it's a sound I have never heard from stock exhaust.

    Gunshot loud noises make others in cars and on sidewalks jump and cops draw guns. If it's that loud I have no idea what is wrong, but something sure is!
    #20