[bobcowan]

The central bell crank connects to pedal to the carb linkage. The bell crank will not - if installed correctly - change the relationship between on carb and another. it will have no effect at all on balance.

You can easily change the pedal sensitivity (to a point) by changing the ratio there. You can also move the arms around to be more or less than 90* to fit a custom application. You can even move the pivot point around a little bit to make the throttle actuation slightly progressive. Less sensitive at lower throttle opening, and more sensitive at the upper ranges.

The kind of bell crank you have is probably the best, as you can make a lot of adjustments between the carbs and the pedal to get the exact right arc of movement that you're after.