It helps to put on a little more traction. The rotor will stay on better because it is not as slippery.

The function of your brake rotor is to apply pressure to the brake line which will help your vehicle stop. The pressure is applied when you engage the brake pedal. The rotor also helps to maintain and control the heat that is caused by any friction when braking.

Remove front wheel, remove caliper from hub, remove small counter sunk screws from rotor then knock off. rebuild in reverse. Hope this helps

So as to start the motor because reactive power helps create the magnetic fields in rotor.

first you need to get a diagram that shows you were number one plug wire goes, and then the rotor should be pointing at it when the motor is a tdc, but if it helps mie was facing the drives side.