CyberPoet's preference: Morgan CarbTuneII (shown here in action):

Morgan CarbTuneII in action
Synchronizing the carbs :

FOR VACUUM DIAL GAUGES: Caution: do not run dial gauges without the in-line shut off valves. Start with the valve closed, open slowly just until you stable reading.
I bought a 4 gauge system ( 1 wasn't functioning properly )
so i just use 2. After removing the vacuum caps  and attaching the hoses & reclaiming the carbs - i close off the plastic inline clamps.
( the vacuum line off carb #4 is larger than the rest so you will have to reduce that line to connect it to the gauge - any auto parts store will sell a little plastic part that does this.

With the bike warmed up and a house fan to keep it cool turn the idle up to 1750 rpm's. calibrate the gauges - pick ONE carb - connect it to all the gauges one at a time and adjust so they all read the same. With them calibrated, adjust carbs 1 to 2, then 3 to 4 and finally adjust carbs 1 to 3. The adjustment screws are between the carbs 1-2, 3-4 and to balance 1-2 to 3-4 the adjuster is between 2 &3.

I have found that it's easier to unbolt the metal frame that is attached to the airbox. then loosen the carb clamps on the engine side and rock the carbs and airbox in one piece to the rear to gain access to the vacuum plugs.
syncadj.jpg (14608 bytes)

The vacuum reading is not important - just that they are all equal
Once they are all reading the same shut down the bike and remove the sync gauge and reinstall vacuum caps & clips ( which means disconnecting the carbs again ! ). reset idle speed.

(sorry about the blurry pix - but you get the idea)