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What's a Plug Chop?

Discussion in 'XJ Technical Chat' started by yamaman, Apr 6, 2010.

  1. yamaman

    yamaman Member

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    :oops: :?: that's it, just the one question
     
  2. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    A tuning technique.

    It involves running the bike at load, at your chosen "target" rpm then hitting the kill switch and pulling in the clutch. You then coast to a stop and read your spark plugs. It will give you an idea of what the motor was doing at the point you "chopped" it, in terms of rich or lean.

    The true value of the technique is open to debate; I personally am not a great believer, but there are others who will certainly disagree.

    Do a forum search, there have been a few lively discussions.
     
  3. grimreaper169

    grimreaper169 Member

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    NASCAR does it so.........
     
  4. Maxim-X

    Maxim-X Well-Known Member

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    ...comes from a pig, oh, wait a minute, I thought you said PORK chop! :roll:
    :twisted: :twisted: :twisted:
     
  5. lopezfr2

    lopezfr2 Member

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    wouldnt it be easier/faster/more accurate to just get a colortune?
     
  6. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    That will only tell you your mixture conditions at idle, without any load.

    Plug chops can be performed at any rpm, are done under load, and under vary conditions (cruise, part throttle, wide-open throttle, etc.) and thus can, with experience, help an engine tuner understand what is happening inside the combustion chamber under a variety of conditions.

    Pain in the butt to do correctly, though, as it's a lots-of-trials-and-lots-of-errors process. Which is why most people don't do them, and the ones that do, tend to do them improperly, and then go adjust things based upon erronous or incomplete info.

    Putting pods on a bike is a good way to insure that you'll get lots of practice at plug chopping!
     
  7. RickCoMatic

    RickCoMatic Well-Known Member

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    To do a successful "Plug Chop" you need some place where you can go to run the Bike up ... Kill it ... and coast to a little work space you have set-up to get the Chop done and do a few others until you get the 1-Hole, 2-Hole, 3 Hole and 4 Hole adjusted to a specific level of Fine Tuning.

    Each time you stop ... you pull the Plugs and see how she's performing at the TWEAK you have just done.

    You can do the same thing without all the fuss.
    Technically, it's the same thing as a Plug Chop.

    The Technical Term is: BaseLine Tuning.
    Get a Base Line established. Know where you ARE!
    Precisely <--- !!!

    Steal a handful of Golf Tees and a Bottle of your wife or daughters Brightly-colored Nail Polish.
    Cut the Points off the Tees nice and flush.
    Dress the end flat. Steal a Emery Board while you are lifting the Nail Polish.

    Start a Tuning Card

    Color the shaft of a Tee with Nail Polish. Let dry.
    Insert Colored Tee into Pilot Mixture Screw Hole.
    Use a Razor or Sharp edged tool to scribe a line on the coloroed Tee.
    Scrape the Color off the Tee from the Scribed Line to the end.
    Measure: Using a Highly accurate Scale, Ruler or Device ... the DEPTH to the Top of the Pilot Mixture Screw.

    Record the Values of No-1 thru 4 on the Tuning Card
    This becomes your Baseline.

    Inspect the Plugs
    Determine if the Mixture is Rich or Lean
    Run the Bike for a day or two.
    Inspect the Plugs

    As inspections are done you can Tweak.
    As improvements are made.
    Make a New Tee for that Hole.

    Eventually you will have Tuned the Bike to a state which cannot be improved upon.
    You'll have a Golf Tee with the Depth of the Pilot Mixture Screw saves to allow you to return to your favorite state of Tuning and possibly another for a RICH Cruising set-up and another for LEAN set-up for Harley-Hunting and Track Day.
     
  8. yamaman

    yamaman Member

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    just as i suspected lol, thanks ya'll. I just didn't put it together w/ the 'under load vs. idle (colortune)' thing.

    I searched the forum but I didn't see it in the 'Subject' & didn't want to spend hours reading 'kind of realted' subjects and hoping. Thanks again. SUBJECT CLOSED
     

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