Originally Posted by masi61

Your "light action" rear derailleur is set up wrong. The upper pivot should not be swung back like that. Also, your cable housing is 4 or 5 inches too short. If you like trying to do your own repairs you might want to look at some Park Tools maintenance videos and invest in some cables, housing, ferules, chains, etc... and the tools to do a proper assembly. Also in your first post you say your bike has a "Campagnolo 7800 rear derailleur" - this is not correct, that is a Campagnolo rear derailleur but the 7800 is a Shimano Dura Ace model which is not what you have. You might be thinking of a 980?

BTH the seat-post clamp in the first post is turned the wrong direction - or did you do this on purpose to move the saddle further forward?