where is the z400 idle screw at i cant seem to find it on the carb. thanks for the help

 

Underneath, up front, you need to turn carb to access it, unless you have a angle screwdriver.

 

The z has an idle adjustment on the right side of carb, black **** to adjust idle. Air/fuel mixture screw is on the front side of carb underneath a black rubber gromet. pull off the rubber piece and adjust accordingly.
later sparx