carburetor

Discussion in 'General Questions' started by gator joe, Oct 16, 2014.

  1. gator joe

    gator joe Member

    what is the best setting put your carburetor on breaking in the motor
     

  2. gator joe

    gator joe Member

    what is the best oil to use in the Gurbee Skyhawk
     
  3. jaguar

    jaguar Well-Known Member

    there is no "best" oil. I prefer synthetic or semi-synthetic because I hate exhaust smoke. But use regular oil till its broke in so the rings can seat well.
    Most people set the needle at the lowest position (clip on highest position) before they finally get tired of that crappy nearly non-adjustable carb (without an idle circuit) and get a good carburetor
     
  4. gator joe

    gator joe Member

    Thanks that sounds 100% like what I am going thru .I just wanted to play it safe
     
  5. Fabian

    Fabian Well-Known Member

    Nothing wrong with the standard carburettor. It's simple and easy to set up, and it gives good results in operation.

    Having said that, my preference is a Walbro style diaphragm carburettor attached to a Rock Solid Engines reed valve intake.
     
  6. jaguar

    jaguar Well-Known Member

    what's wrong with the NT carb:
    1) it has no idle circuit
    2) there are no other needles available for it with different angles of taper
    3) it often develops air leaks where it connects to the manifold
     
  7. Fabian

    Fabian Well-Known Member

    If the carburettor is jetted correctly and has no manifold to carburettor air leaks, the standard NT carburettor gives an acceptable idle and an acceptable transition to wide open throttle.

    Alternative needles are not required with this type of carburettor and venturi bore size, because the engine spends little time at part throttle. Even when the engine is used at part throttle, there is enough adjustability in the positioning of the needle via adjustment of the e-clip.

    An o-ring placed in between the carburettor and the intake tube, takes care of any air leakage that might make it's way past the carburettor clamp.

    The issues you raise are easily fixed.
     
    Last edited: Oct 18, 2014
  8. jaguar

    jaguar Well-Known Member

    A common complaint is that when the needle is set right for mid throttle acceleration then the jetting is off for full throttle power.
    Also, how do you "easily fix" the missing idle circuit? answer: you don't
     
  9. Fabian

    Fabian Well-Known Member

    You simply jet the carburettor so the engine is running on the very edge of 4-stroking at max rpm of 5,000, then place the needle as low as possible or seen another way, placing the "E-clip" as high as possible on the needle, and it's job done.

    You will have a carburettor that operates flawlessly at idle and transitions flawlessly when you snap open the throttle, and runs reasonably anywhere in between.
     
  10. jaguar

    jaguar Well-Known Member

    2 strokes run best at high rpm with the jetting just a trad richer than what causes it to seize, not slightly leaner than what makes it 4 stroke
     
  11. butre

    butre Well-Known Member

    running lean in a stock ht will cause overheating very quickly. if you've got the know how to make an ht run hard at high rpm without overheating you're not asking about best oil or carb settings for break in.

    of course with an aftermarket cdi, cold plug, billet head, and maybe exotic fuel it could potentially be favorable to run lean, but that doesn't apply to a whole lot of people.
     
  12. jaguar

    jaguar Well-Known Member

    I think that rule is applicable to both low performance and high performance engines. It's just the way two strokes are.

    Concerning the carburetor; when I switched out from the stock carb to a Dellorto I gained a significant increase in top speed as well as idling much smoother/stronger. The difference was night and day. And the stock carb had been jetted to near perfection, even making the needle fatter with solder on it (the next best thing to buying a fatter one) at its lower 1/3rd. Fabian brags about how good the stock carb is but doesn't use one himself. go figure
     
    piecepatrol99 likes this.
  13. gator joe

    gator joe Member

    Lol I am in total agreement bro. .I am going to by a d. Real soon
     
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