I agree with GB; don't try to take the upper pivot assembly apart and try to mod it. You'll just be opening up a Pandora's box and kack a rare derailleur.

It shifts slower and less responsively, but it shifts the range like it's designed to. If you want something more responsive you'll have to move into a slant parallelogram like a Deore XT M730.


EDIT: I'd take that Arabesque off your hands too!