A coupling system (1) between a motor (10) and an agricultural tool (20), wherein the motor (10) comprises a stiff tubular support (30) and a drive shaft (40) rotatably arranged within the stiff tubular support (30), wherein the drive shaft (40) has a coupling end portion (45) and the stiff tubular support (30) has an engagement end portion (31)； the agricultural tool (20) comprising an outer carter (50) and a coupling shaft portion (60) rotatably arranged within the outer carter (50), and wherein the outer carter (50) has a tubular engagement portion (55)； the system (1) also comprising a plurality of elongated coupling elements (70), each of which consists of a single part having first and a second coupling portions (71,72), configured to be coupled with the coupling shaft portion (60) and with the drive coupling end portion (45), respectively, through the first and second coupling portions (71,72), in order to transmit a torque from the drive shaft (40) to the coupling shaft portion (60), the coupling elements (70) having a predetermined length (L)； a tubular extension portion (80) of the connection between the stiff tubular support (30) and the tubular engagement portion (55), the tubular extension portion (80) having a predetermined extension length (L') at least equal to the length (L) of the coupling element (70).
