Decel popping

Discussion in 'Touring Models' started by kstrohs57, Sep 9, 2011.

  1. kstrohs57

    kstrohs57 Active Member

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    Hello im new to this forum , Would like to ask ? Has anybody had back fire issues after getting tune up/dyno . I presently have my 2004 ultra back for 3rd time @local harley shop to resolve backfire issue . Had no loud(shotgun loud) backfiring prior to original tune up/dyno . The bike has 103 big bore kit etc. & screaming eagle race tuner . Is it very hard to tune with these add-ons ??
     
  2. glider

    glider Veteran Member

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    Re: Inappropriate Language

    An exhaust leak will cause backfiring and a competent tuner should be able to tune out backfiring if the exhaust isn't leaking. After three times, I would suspect the tuner and the way he tunes a bike myself.

    Harley Davidson Community

    I moved your post to the proper forum.
     
  3. horizonchaser

    horizonchaser Senior Member Contributor

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    Glider is right on with the exhaust leaking. I know because I had a wicked decel popping sound on my '03 Ultra. Come to find out I had a cracked exhaust pipe. They replaced the cracked pipe and it doesn't pop nowhere near as bad as it used to. Look into that.
     
  4. kstrohs57

    kstrohs57 Active Member

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    Thanks for reply , local harley shop in Mansfield Ohio finaly got the dyno/ tune correct - no loud shotgun back fire -just nice rumble on de-acceleration took 3 hrs & gained 1.5 hp from 90 to 91.5 & torque from 93 to 97 . Im HAPPY :) .
     
  5. R. Lewis

    R. Lewis Senior Member Retired Moderators

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    So what was the culprit causing the backfire???? 3 to 4 dyno runs just hurts me to read about it!!!! WOT that many times!!! AAAAAUUUUUGGGGGHHHH!!!!!
     
  6. kstrohs57

    kstrohs57 Active Member

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    I asked the ? does dyno runs stress your bike to the max & was told that dyno runs were not destructive in any way ? I still would not recommend repeat dyno runs like this .The basic problem with the de-acceleration back -fire was caused by air/fuel mixture not being correct . Now set @ 1.32-1.34 prior runs look to start around 1.43 & go down to 1.3 now the air/fuel mixture is steady @ 1.32-1.34 & there is no more shotgun back fire . There was no exhaust leaks , so it had to do with the air//fuel mixture with the screamng eagle race tuner .