Discussion in '2-Stroke Engines' started by ParadoX, May 2, 2010.

  1. ParadoX

    ParadoX New Member

    Hello, Ive searched the forums and have read the carb adjustment threads, but am still having an issue.

    With my e-clip at the 2nd postion, the bike run bad. 3rd position, It rides pretty good, but I have some 4-stroking at higher speeds. Without any other positions to try, how can I fine tune the carb to get a little more air in?

    Ive got a boost bottle and sbp pipe if that matters. Carb is the newer grubbee 'speed' carb.

    Any tips?

  2. AussieSteve

    AussieSteve Active Member

    It sounds like you might need to go down to a smaller main jet.
    With my stock NT carb, I had to go down from 0.79mm to 0.72mm to get my mixture lean enough and still have the slide needle on it's lowest setting.
    Does the 'Speed' carb only have 3 notches on the slide needle? (The original NT carbs had either 4, (earlier model), or 5 notches, (later model).)
  3. Biker

    Biker New Member

    do the main jets have numbering on them,mines an NT,Needle is set the same as yours,so i need to go down on main jet to.Mines a 48cc
  4. AussieSteve

    AussieSteve Active Member

    G'day, Colin.
    Unfortunately, the stock NT jets don't have the size printed on them and neither did the one I got from Rock Solid Engines.
    The ones that I got from OzMiniMoto were numbered, though.

    You can probably assume that you have an 0.79mm jet.
    Mine's a 66cc, and I found that an 0.72mm was best.
    Maybe you could start there.
  5. Biker

    Biker New Member

    Thanks Steve for the quick reply,i may take the jet down to the local mower place then and get him measured first off