If you sinc the carbs with gauges while the motor is running, you may be mildly adjusting the air-screws at idle or modest rpms to get the smoothest possible idle. Adjusting later by feel and sound can be done after some miles but typically requires personal experience with the bike to know its normal sound versus a slight irregularity. If you adjust before you sinc with gauges, your testing your ability to tune by sound and feel..........that might be a good thing to know when your on the road. Maybe I'm just lucky.......I took a set of carbs off of a blown K4 motor about five years ago. I sonic cleaned them and put em on the shelf. Now I dusted them off and put them on a rebuilt K5 motor and they started right up and idled fine with a K&N in the airbox. I won't have the rest of the drivetrain together for a while so a test ride will have to wait to see if they need any tuning.........but I dought it.
