Carby CNS Carb. How do?

Discussion in '2-Stroke Engines' started by MszTheBehr, Dec 11, 2013.

  1. MszTheBehr

    MszTheBehr New Member

    I just got my Cns carb, and I am completely baffled by how to tune it, or there the various life support tubes go. I've got a 66cc skyhawk engine. Any snippets of help would be greatly appreciated. :confused:

  2. jaguar

    jaguar Well-Known Member

    just route the tubes downward and out of the way of the chain. (except for the fuel supply line).
    google "carburetor tuning guide".
    you can buy new jets (fuel regulators) or you can use the method I outline on my site to southern engineer the jets that come with the carb.
  3. Leroybrown420

    Leroybrown420 Member

    Jaguar, are you refering to "southern engineer" as drilling & filling the jet?

    Behr, the two top ports need the plastic tubes, they are air vents and just float in the breeze. If you have Grubee CNS then the bottom port is a overflow drain. I like to extend the tube downward by the kickstand and secure it with a ziptie. If you keep the drain tube short you will get fuel on your feet. If you have the non-Grubee CNS then the bottom port (the drain) is routed back to the carb and recycled to the engine (better choice).

    From my experience, the stock NT carb works better. For some reason CNS carb act like they are running out of fuel (cutout) at speed. Keep in mind that the choke circuit is different than most carbs too. CNS carbs have extra jet that allows addition fuel for cold starts. Don't leave it open to long of you will flood your engine & foul the plug. It can be cracked open when hill climbing or when running flat out.

    Adjustment screws: Grubee CNS have only the idle speed screw (in for higher idle, out of lower idle). The non-grubee CNS has an additional fuel mixture screw.

    Hope this helps and Good Luck!
  4. Leroybrown420

    Leroybrown420 Member

    Grubee CNS

    Non-Grubee CNS
  5. Fabian

    Fabian Well-Known Member

    That exactly mirrors my experience, and i have tried (and rejected) the Genuine Delorto SHA, the Delorto SHA Clone and the CNS.
    Every time i came back to the NT as my choice of float style carby, of which the NT (with nothing more than optimised jetting) works with surprising functionality and reliability.