Initial set-up:
Idle speed: Got a good drill bit set? Select the 9/32" drill. Screw the idle speed screw (knurled screw w/exposed spring) in or out until the shank of the 9/32" drill slips under the slide at the filter end. Repeat for the other carburetor.
Cable slack: choke cables and throttle cables should have around 3/32-1/8" slack. Adjust them so that the left and right of each are as close to the same as possible.
Idle mixture: turn the idle mixture screws (down in a hole, no exposed spring) in until the seat, then turn them out ~ 2 turns.
Sync'ing the carbs: Engine not running. Open the throttle slightly and use the friction screw on the twist grip or other means to hold it there. Use a larger drill bit in the same manner as dscribed above to measure the opening height of the slides. If one is higher/lower than the other, use the cable adjuster on the top of the carb to adjust the slide up or down as needed. Make sure you still have adequate slack when at the idle position. This will never be as accurate as syncing with a vacuum manometer.
Adjusting idle mixture: Start the engine and bring it up to normal operating temperature. Slowly turn an idle mixture screw in, listening and feeling for the engine to just begin to slightly slow or falter, turn the mixture out 1/2 turn. Repeat on the other side.
Works for me. YMMV.
