An agricultural baler comprising a baling chamber with a plunger that is provided to reciprocally move in the baling chamber, the baler further comprising a pre-compression chamber with a slice pushing mechanism provided for periodically pushing a slice of crop material into the baling chamber, the plunger and the pushing mechanism being mechanically linked via their respective driving systems to ensure synchronization, wherein coupling means are mounted in the mechanical link, the coupling means being provided to adjust a synchronization timing.
