This is the center of the main jet stack, and it has small holes in the sides. The rating on this type is BE1-BE5. These ratings don't seem to have any rhyme or reason. For example, a BE4 does not necessarily let in more fuel than a BE2. Most people leave this stock and work with the main and air jets.
Jetting is something that takes trial and error. See our blog page of for more info.
Atomizer Jet (BE5); SI Carbs
Dellorto SI Jets
Have a Question about this item? Click here to email us.