Many like the increased horsepower and better fuel economy when you jet down, but don't like the worry of being too lean. The ability to adjust your jetting to one of five settings with the twist of a screwdriver is only part of it - the greater benefit is to be able to run leaner without worrying about damaging a motor. We felt this to be one of the most noticeable benefits - our ZR 700 really woke up coming out of the corners and had a nasty holeshot. It not only ran crisp all of the time, but the quicker throttle response was an advantage. The finer spray of fuel ignites faster and more completely, helping to burn the heavier, denser fuel being delivered by the other circuits of the carburetor.
Fuel only flows up to the mixing chamber when the engine is under load and needs it.
This is normal. The dual system increases the amount of pre-atomized fuel being delivered. The entire system becomes less sensitive to changes in altitude or temperature. It is performance, convenience, and insurance in a single package. It could be the best money you will ever spend on your machine.