GREAT QUESTION on PLUG CHOP?

Discussion in 'Motorized Bicycle General Discussion' started by Geebt66cc, Nov 27, 2012.

  1. Geebt66cc

    Geebt66cc New Member

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    Uno, I was sitting here thinking of why these little carbs on the bikes. NT,SPeeD,CNS,etc...........Is the only reason that they have the needle adjustment on them, is because they are on such a erratic opperating engine? See, the better carbs don't even have that needle adjustment, you just change out jet size. Think about it, you've never had to switch out needle positions on a better QUALitY 2/stroke, and for that matter, very few ever need to be re-jetted ................( Better 2/strokes engines, you just worry about getting oil ratio right)

    Ok, Ok, question is (Why do these HT'S need needle adjustments?) ..........Mmmm, they are so cheeply made, they need constant checks?.........Is it just do to quality? Or is it because they want to make the owner feel like they are the mechanical WIZ??????????????????----Uno, wanting owner to bond with there engine?

    TY,GLEN
     
  2. GearNut

    GearNut Active Member

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    Huh?
    Most all engines need the clip position tuned. The "better" carbs you speak of really should have adjustable slide needles.
    Atmospheric conditions such as the altitude you live at, outside temperature, and more, all have a big impact on the engine's state of tune. Changing the jets to tune a carb is all fine and dandy, however it re-calibrates the fuel to air ratio in large jumps. Adjusting the slide needle allows even finer adjustments when combined with tuning the jet size.

    Just because these "better" carbs don't give you the ability to tune the needle position does not mean that they don't need it. Quite the opposite actually.

    It is that fact about them that I have issues with calling them "better".

    Most of them have been released after the EPA and CARB Nazis tightened up the import restrictions even more and now the factories are required to "pre-tune" the engines to pass the import exhaust emissions standards requirements. They use fixed position needles and capped (sealed off) low speed mixture screws to try to prevent the end user from re-tuning the engine and increasing the unwanted emissions. This is all done by import law, not necessarily by the factory's choice or preference.

    The whole notion of a "pre-tuned" carburetor is horrible!
    Just ask anyone who lives up in the hills how well an out-of-the-box engine runs.
    Ask them to never ever tune the engine, no matter the reason.
    Will they be happy with it? NO!
     
  3. 2door

    2door Moderator
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    Everyone wishes they had a fuel delivery system that never needs adjustments. Ask any professional engine tuner in drag racing or for that matter any motorsport. The advent of computer controlled systems in today's cars have pretty much taken the responsibility out of the owner or the mechanic's hands but you can be sure that the little electronic brain is making constant adjustments as you drive, as the humidity/temperature changes as you accelerate or decelerate, climb a hill or use cheap gasoline. Same for the ignition system.

    If you're fortunate to have an older carburetor that can be easily adjusted, be thankful. There might come a day when they'll come from the factory completely sealed and become a throw-away item, like flashlight batteries.

    Tom
     
  4. rustycase

    rustycase Gutter Rider

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    Yup!
    What Gearnut says, and more!
    More adjustments the better, especially on tiny little motors...
    rc
     
  5. Greg58

    Greg58 Well-Known Member

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    Well put GN, I own two antique vehicles that have carburetors . Both need adjusting from time to time, something as simple as a 25 degree temperature drop will change the performance. Before on board computers and engine management all vehicles needed carb adjustments from time to time.
     
  6. Greg58

    Greg58 Well-Known Member

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    Sorry Tom you beat me on this reply, its funny we said about the same thing!
     

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