Carby Too rich? or not rich enough?

Discussion in '2-Stroke Engines' started by CPC, Apr 12, 2009.


what notch do you use on your carbs needle?

Poll closed Apr 26, 2009.
  1. The top one

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  2. Second from the top

  3. Third from the top

  4. Bottom one

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  1. CPC

    CPC Member

    Ok, so hears a question, how rich is too rich? My engine is running a 20:1 gas/fuel mixture the needle is @ the 2nd to the bottom notch. I leave a trail of smoke even at 20 Mph! Do I need to run this rich, even though these are scavenger engines and I run wide open 70% of the time? How rich do you run? FYI I am in a semi-desert so dust storms are often, and have an altitude of around 1472 meters (4829 feet), I also have about 150 miles on this engine.

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  2. arceeguy

    arceeguy Active Member

    At that altitude, you probably want to raise the clip (lower the jet needle) and get a smaller main jet. I think someone here has mentioned that dellorto jets will fit, and you want to start out at a #65.

    Here in NJ, at sea level, I run jets hogged out to .75 -.80mm so they don't lean out. You need to go the other way because of your thinner air.

    Note: I did not vote in your poll because jetting is variable depending on conditions. What works for some my not necessarily work for others.
  3. CPC

    CPC Member

    I want the CNS carb that spookytooth is selling for $35, its for a 66 cc not what were getting stock for a 48 cc.....have you tried that yet?
  4. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    Some of the needles on the stock Chinese carb's have 5 clip positions
    although the majority have 4

    PS: Make sure your jet is screwed in firmly from inside the float bowl
    as loose jets that unscrew themselves are fairly common
    Last edited: Apr 12, 2009
  5. CPC

    CPC Member

    mine has 4