posted last week that i got my new carb sync tool(vacuum type) and went at it. it was a little off. i got all the cylinders to read the same, but low around 5. (the outer numbers on the gauge). i went for a ride that eve, about 40 miles . yesterday i hooked up the gauges again and to my surprise the vacuum was lower than before.the clymer manual states between 16- 24. mine are at 6, cant get the any higher.some on the previous post thought a air leak. but all 4 carbs read the same. the main reason for the carb sync was because of a racing idle. it either revs to 3000 or dies under 1200 rpms, i have to always mess with the main idle screw at stops. the bike now seems uneven at lower rpms but over 5000 it sounds great and pulls hard. i know its not the motor since the original lost a cam chain last year. the current motor is a used junkyard with only 3300 miles on it and the racing idle is still there. the carbs have been apart for cleaning and they dont leak a drop. could the carb gaskets themselves cause the air leak? cant see what else it could be. btw the bike is 76 cb 550k w/ mac 4/1, and a uni air filter. the carbs are stock original. btw mixture screws are 1/2 turn out each. thanx in advance carl