how much of the threaded stud is stickin out of the top of the 10mm lock nut on top of the carbs?????

if you have synched your carbs and weren't carefull to get them adjusted to spec (16inches of vaccum I think??) with no more than 2mm of stud stickin out the top, it will cause your idle to be high and not come down......usually I spot that problem cause the idle adjust screw is out all the way and the idle doesn't change.