What do you need to synchronize two carburetors?
Now comes a part of synchronization that is usually overlooked. You want both carburetors to have identical throttle positions at all points (NOT just idle). You also need both carburetor adjustments to be unaffected when sitting at idle position (same carburetor position with linkage attached as when it was disconnected).
What happens when your CARB is out of sync?
When carb sync is out of whack, you can have a poor idle, poor off-idle response, “hanging” throttle and lazy return to idle. You can even suffer from fouled plugs if one or more throttle butterflies are opening early, thereby partially activating the carb’s progression circuitry. Very small adjustments will have a major impact on idle smoothness!
What happens when you put Uni-Syn on carburetor?
Now, when you put the Uni-syn on the top of the carburetor (one throat), you need to rotate the disc (that is on the threaded piece) up or down to center the piston in the glass. It doesn’t matter how much air is moving through the carburetor now, as long as the engine’s idle speed doesn’t change when you put the Uni-sync on the carburetor.
How to sync and tune a CB750 carb?
Make sure the play in each carbs cable is the same. Turn each carb air screw until it seats, then back it out 1 full turn. Reinstall the airbox. Start the engine and warm it up to operating temperature. Remove the vacuum plug holes in each carb body and screw in the vacuum gauge adapters. Set the idling speed to 850 to 950 RPM.
How many carburetors do you need to synchronize?
This carb sync procedure can only be done on TWO or more carburetors. This adjustment should be made with the engine at operating temperature AFTER all pilot screw adjustments have been made and the bike has the ability to run at idle. * This is caused by what is called “power pulses”.
What happens if you discontinue carb synchronization procedure?
THERE IS A DANGER OF SUCKING MERCURY INTO THE ENGINE IF YOU DO. IF THIS HAPPENS, DISCONTINUE THE SYNCHRONIZATION PROCESS AND RIDE THE BIKE FOR ONE MILE OR MORE TO PURGE THE MERCURY FROM THE ENGINE. NO DAMAGE TO THE ENGINE WILL OCCUR IF THIS PURGE PROCEDURE IS FOLLOWED.
Now, when you put the Uni-syn on the top of the carburetor (one throat), you need to rotate the disc (that is on the threaded piece) up or down to center the piston in the glass. It doesn’t matter how much air is moving through the carburetor now, as long as the engine’s idle speed doesn’t change when you put the Uni-sync on the carburetor.
How do you synchronize two carburetors in a VW?
So next you adjust the little set-screw which is the throttle stop, and which is the idle speed adjustment on these carburetors. Turn the screw in (clockwise) to flow more air, and out to flow less air. You want to match the intake airflow from side to side on the engine. Now, here’s my little trick.