The OP must have the housing and cable kinda kinked up in the top tube so there might be a coil looped up in there that's causing the not so positive initial pull feel at the lever. I suggest that he grab the housing at both ends near where the comes out of the top tube and try to see if he can maybe pull that kink out. He should feel the cable and housing get longer if there is a kink in there.
I also doubt if there are "rings" inside the top tube as that's just the dumbest thing that a bike manufacturer can do to design internal cabling for their bikes and how the heck can they even attach small rings deep inside a top tube??......