Carb Sync Methods

 It is important to understand, no matter what method is used, that carb sync is the act of attempting to get the slides positioned so that they all pass the same airflow at ANY given throttle position.  That cannot be done if any slide is resting on an idle stop screw or bottomed out.

A manometer or Uni-Syn can also be used and may obtain better results IF used properly.


Method 1: (Aylor)

 1) First back off the idle screws till they don't touch the slides.

 2) Carefully screw each one in until the screw just barely touches the slide.

 3) Turn in each screw the exact same amount, until you get your target idle number.  If you don't do this first, the little variance you get when setting the idle screws will affect slide height and the sync will not be "spot on".

 4) Make sure you have slack in the cables.

 5) Put your middle finger of your left hand on the center slide, and your thumb (left hand) on the right slide.  Turn the throttle very slowly and feel if the slides lift at the same time.  If not, adjust one or the other cable so they do.

 6) Snap the throttle a couple of times to make sure the slides are setting in well, and tighten the cable lock nut and recheck.

 7) Move your thumb to the center slide and your middle finger to the left carb.  Adjust the LEFT carb till it lifts exactly with the center.

 8) Snap the throttle again and make sure the lock nut is tight (tightening the lock nut will change the slide height).

 9) Take out any extra slack in the cable, AND check the oil pump for correct setting.

I use the finger method because a finger can tell movement in thousands of an inch (just say very accurate).  I prefer to set the sync from idle, because that is where I feel it is most important.




Method 2: (mraxl)

1) Find a smooth round pin about 3/8" or 10mm dia. (I use the shank of drill bit)

2) Remove air box/filters.

3) Back out slide stop (idle adj) screws.

4) Set throttle lock or set throttle adjuster at the grip so the pin will just lightly drag as it is inserted in the carb throat under the slide cutaway of one carb.

5) Set the other carbs so they offer the same resistance when the pin is inserted by setting the cable adjuster at top of each carb.

6) Release throttle lock or reset throttle adjuster at grip insuring that slides on all carbs will fully bottom out and throttle grip has 2-3mm play.

7) Set air & idle adj screws per manual or for best idle.

As a final check to insure all idle adj screws are set the same, insert a nail, spoon, or long toothpick under each slide without altering slide position.  As the grip is turned the ends of all three should tip at the same time.  Readjust idle screws as required.

Carb Sync Video by Darth