found some article here
its a good read… !!
In Short.. its not good to have more PRIVATE methods in your class.
if you have more methods that depends on some behaviour.. its better to have abstracted them. i.e have an interface and declare all your behaviours in the interface and have the class implement this interface.. so that you will abstract the behaviour in to a concrete class and if ever this behaviour were to be changed, you will do changes in the concrete class.. by that way you will be adhering to single responsibility principle and open closed principle