In a small saucepan, bring water and sugar to a boil. Cook and stir until sugar is dissolved; set aside to cool.
Place the evaporated milk, orange juice, lemon juice and banana in a blender. Add the sugar syrup; cover and process until smooth.
Pour into cylinder of ice cream freezer; freeze according to manufacturer's directions. Transfer to a freezer container, allowing headspace for expansion. Freeze for 4 hours or until firm before serving.