Silly Exhaust Sound...

Discussion in 'General Harley Davidson Topic' started by Oscar, Aug 23, 2010.

  1. Oscar

    Oscar Member

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    ...at least I think it's silly, but it's been bugging me. Every time I ride over a bridge, or overpass, or similar structure, my exhaust takes on a high pitched, sort of whistling sound. It does this without fail and without regard to wind speed, my speed, etc. I'm assuming it's just the wind hitting the ends of the Rinehart pipes and making a sound like blowing into a jug, I just find it interesting that it never fails.
     
  2. Joyflyin

    Joyflyin Experienced Member Staff Member Moderator

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    I would venture to guess that you are hearing the noise of the bike bouncing off the walls of the bridge. My bike does this too & that's what I think is happening. It probably has a technical term, but it's late & I'm tired. :)

    Now, let's sit back and see if we both learn something. :s
     
  3. Jack Klarich

    Jack Klarich Expert Member

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    Harmonics?:s
     
  4. Joyflyin

    Joyflyin Experienced Member Staff Member Moderator

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    Could be there Jack. :D I kept thinking reverb, but I'm pretty sure that is not the technical term in this case. :s I'm off to bed, it's been a very long day. Hoping the brain will be clearer tomorrow.
     
  5. NEWHD74FAN

    NEWHD74FAN Experienced Member Retired Moderators

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    Exhaust sounds different in canyons or when riding with other HDs, that rumble whan bouncing in and out of harmony with the other bikes is a sound truly like rolling thunder. I think the term Jack and Joy are thinking is "Doppler effect" that change in pitch higher or lower as vehicle gets closer to you or farther from you. I also like the sound reflections when you pass sound barrier walls or metal bridge trestles with cross beams the metal scrolled grating humming underneath. I think it is kinda neat, a virtual concert goes on, especially with the half helmet. Enhanced sensations of sounds AND smells...you know your really enjoying the ride if that is what you remember, that first grove of tall trees and you here the echos reflecting back...hey its' Monday, and I am stoked...tomorrow is another motorcycle ride away...ENJOY!
     
  6. Jack Klarich

    Jack Klarich Expert Member

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    HMMM, I like your answer better than mine, I have turn outs by cycle shack with modified baffles by me and I like the Doppler Effect,I knew some one on the Left Coast would have the right answer:p
     
  7. billyd1

    billyd1 Active Member

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    There is some kind of exhaust valve in the system on my RKC that I hear the same way you describe. I believe it helps with torq but I've yet to see one apart to understand it completely. Kinda squeals like a hog! :p
     
  8. Jack Klarich

    Jack Klarich Expert Member

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    Thats cause your riding a Hog remember? LOL:p
     
  9. billyd1

    billyd1 Active Member

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    :lolrolling Gotta have my pork:D I see it in my manual listed as the "Active Exhaust Valve"
     
  10. murf

    murf Active Member

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    "sound rebound" ? I like it.