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Thread: 1973 Shovelhead Oil Pump Isuues Help ???

  1. #21
    Join Date
    Jun 2019
    Location
    Pennsylvania
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    23

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    Got em Robbie, Thanks ! See, this info you provided me proves you're a TRUE "Harley God" !!! Tim

  2. #22
    Join Date
    Jun 2019
    Location
    Pennsylvania
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    FREE Beer for sure ! That's why I stated, "completely outfitted". There'd be a Brewery on site (first things first ya know) !!! Good Luck with the Carby, I'm sure you'll figure it out. If not, bring it to that shop we're gonna build and grab a beer while it's gettin repaired !!!

  3. #23
    Join Date
    Nov 2018
    Posts
    154

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    The float that was fitted doesn't float, very useful for something I suppose, but not carbies.
    Installed an old cork float and got the bike running. First time it has run for maybe 50 years.
    Set off every smoke detector in the house.
    Runs like **** still, but I will keep tuning until it is good.

  4. #24
    Join Date
    Nov 2018
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    154

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    Twister,
    I was thinking about the oil pumps and remembered the pressure relief valve has another function that might directly affect your problem.
    The oil pump is a positive displacement gear pump, which means every time it rotates, it will pump a fixed amount of oil. This generates preesure against the pressure relief valve spring.

    When the motor is running at low revs, the oil pump pushes the relief piston up until it opens up the first port. This port feeds the tappets and top end, and is relatively large.

    As the revs increase, the pressure increase until the piston is raised a bit more and opens up the second, small, port to the crankshaft oil feed.

    As the revs increase further, eventually the pistons is pushed up until it opens up a port that relieves the pressure.
    Depending on the year, this oil goes to the cam chest, or back to the oil pump feed line.

    Harley used this arrangement to ensure the tappets always had an adequate oil supply to the Hydraulic lifters at low revs

    This is part of what the drilling passages, plugging ports etc is about that S&S recommend to update earlier motors.

  5. #25
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    Jun 2019
    Location
    Pennsylvania
    Posts
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    WOW Aumick, a 29 JD ? I'll bet it's real nice, wanna make a trade ??? Thanks Again for taking the time to help me, when you're having troubles yourself ! Really appreciate the info and "FREE" education ! Tim

  6. #26
    Join Date
    Nov 2018
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    154

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    Quote Originally Posted by Twister the fitter View Post
    WOW Aumick, a 29 JD ? I'll bet it's real nice, wanna make a trade ??? Thanks Again for taking the time to help me, when you're having troubles yourself ! Really appreciate the info and "FREE" education ! Tim
    Your welcome,
    Sometimes it is best to walk away for a while when facing problems.

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