Dont think they are pre-set, but they are always in the neighborhood. Its actually easy to check on these- just make sure that seam in the float is level with the carb body just as the the tang begins to engage the needle valve.
Cripes on the Yam XT you ned to make a separate clear tube and make sure the bike is level and then figure out 6mm below the carb seam... Makes the BMW seem no-nonsense.
"Why BMW? You like to suffer? My sister, she has five kids, no husband. You come over?"