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Hard knock front cyl

Discussion in 'Motorcycle Tech Talk' started by Ironrider57, Apr 21, 2011.

  1. Ironrider57

    Ironrider57 New Member

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    First of all I am new here and would like to say thanks up front foe a site like this. I am having a problem with a hard knock in front cylender under load or at idle. I now have noise in bottom, sounds like a loud rattle or spinning. Any
    sugestions on what this could be?
    Ironrider57, Apr 21, 2011
    #1
  3. Tommyc

    Tommyc Active Member

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    Wow, that is scary.
    I cant help, sorry. Maybe a mechanic on this site can offer some ideas as to what it might be.
    Is the motor stock or does it have any modifications? Has any work been done on the motor recently?
    Is the noise coming from one specific side of the engine or no?
    Tommyc, Apr 21, 2011
    #2
  4. JohnnyBiker

    JohnnyBiker Well-Known Member

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    And what kind of bike is it and what motor???
    JohnnyBiker, Apr 21, 2011
    #3
  5. Tommyc

    Tommyc Active Member

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    profile says 03 heritage.
    Tommyc, Apr 21, 2011
    #4
  6. JohnnyBiker

    JohnnyBiker Well-Known Member

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    Ooops, didn't notice.
    JohnnyBiker, Apr 21, 2011
    #5
  7. cowboy

    cowboy Moderator Staff Member

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    noise can travel or sound like it comming from one spot & be it another, A long screw driver can help you locate it , put the tip on engine & handle next to your ear & go around all the engine you'll here the sound cause it will be different then the rest
    cowboy, Apr 21, 2011
    #6
  8. JohnnyBiker

    JohnnyBiker Well-Known Member

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    Cowboy is not kidding about this at all. I had a baffle that came loose and I thought the noise was coming from the transmission, then it sounded like it was coming from the heads, then I thought it was coming from the crank area. So be thorough when you try to locate it.
    JohnnyBiker, Apr 21, 2011
    #7
  9. whacker

    whacker Active Member

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    I had a hard knock on my rear cylinder on my 75 Sportty...ended up being the crank pin,hope you find your knock..
    whacker, Apr 21, 2011
    #8
  10. cardboard

    cardboard Well-Known Member

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    Hmmmmmmmmmm

    Ever thought about gettin a perfessional opinion from a Indy shop or the dealer ?
    cardboard, Apr 21, 2011
    #9
  11. hotroadking

    hotroadking Super Moderator Staff Member

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    Compensating sprocket loose
    Piston slap
    Cam bearings going out
    Cam tensioners shot
    Lower end bearing
    Bad rod or cracked rod
    Broken mount

    Get a mechanics stethoscope
    Let it warm up and idle and go around different places and listen
    For sound


    Sent from my iPhone using Tapatalk
    hotroadking, Apr 21, 2011
    #10
  12. chucktx

    chucktx Moderator Staff Member

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    as long as it is makin noise your riding!!!! when it stops makin noise your walkin...........:)
    chucktx, Apr 21, 2011
    #11
  13. FLHTbiker

    FLHTbiker Moderator Staff Member

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    Good one, :cheers:
    FLHTbiker, Apr 21, 2011
    #12
  14. more power

    more power New Member

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    :eek::angry::roflmao: That's one way to find it. Don't ride it unless you have your walkin shoe's with ya.
    more power, Apr 24, 2011
    #13
  15. Tommyc

    Tommyc Active Member

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    Anybody know what the problem was?
    Tommyc, Apr 29, 2011
    #14
  16. Tommyc

    Tommyc Active Member

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    Harley's have roller bearing so they don't spin like a car's engine would so what happens when an engine bearing goes bad? Do they just disintegrate and blammo!
    Is it rare for a harley to have an engine bearing failure?
    Anyone have any experience with this?
    Tommyc, Apr 29, 2011
    #15
  17. chucktx

    chucktx Moderator Staff Member

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    rod bearings wear abnormally due to lugging the engine.....keeping the engine above the 2k mark will let them last a long time. lugging is one of the worst things you can do to an engine.........
    chucktx, Apr 29, 2011
    #16
  18. cowboy

    cowboy Moderator Staff Member

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    What carb areyou running?
    cowboy, Apr 29, 2011
    #17
  19. Tommyc

    Tommyc Active Member

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    The rod bearing are 1 piece like a cylinder shaped bushings, correct? They won't spin like a car engines. I guess they just wear from the friction, become loose and them knock. I don't know fer sure tho.
    Tommyc, May 2, 2011
    #18
  20. fxdxriderleo

    fxdxriderleo Active Member

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    The rod big ends are caged roller bearings, the small end solid bronze bushings.
    Leo
    fxdxriderleo, Jun 9, 2011
    #19

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