First, make sure the throttle cable has enough slack that the idle screws are actually in control. Check for binding in the throttle cable by pressing the throttles down against the screws after using the grip to open them; they should not move. Make sure the throttles are in the same relative position; if not, the splitter may be at fault, and one cable has jumped out of its holder. Next, make sure the carbs are locked into the grooves in the inside of the intake boots, and that the bolts holding those boots are tight. Check static timing, and make sure the springs are holding the weights against the inside stops; turn the cam with your fingers, and the weights should fully return. Then check timing with a light; this is less messy if you have a spare alternator cover you can punch a hold in over the timing marks. At that rpm, it should be fully advanced, but stable; not bouncing around or above the full advance marks.
