This giant robot is created by combining the space bikes (Monsoon, Typhoon, Reppoon, Hurricane, and Cyclone) ridden by the top five members of the Ginga Reppu Squadron, enlarged through the Synchronization Principle, and then combining through Synchronization.

It possesses a unique combining mechanism, even within the series, which allows unnecessary parts to be stored internally by partially synchronizing. It is the only J9 series main robot to have five fingers. Bakushinger is also the only robot to be referred to by the program name, including the "Ginga..." part, in the main story. Stecken had the developers build it through Three J (with almost no expenses).

It was designed for mass production (robots like this were fairly common during the time of "Ginga Reppu Bakushinger"). Five sets of mass-produced Bakushingers were supposed to be produced, each with brainwave control of five bikes by one person, but due to a lack of time and funds, only one was ever made.

It boasts overwhelming performance in the story, and combined with the pilot's skill, it instantly kills most enemies. However, individual strength alone was not enough to overcome the overwhelming numbers of the New Solar System Alliance, and although the Ginga Reppu Unit continued to win battle after battle, the situation gradually worsened due to the betrayal of comrades. Towards the end of the story, Diego was killed charging in with the mass-produced Bakushinger to protect his hometown, and Sama was assassinated by Gilles Claude's subordinates, making the combination impossible. In the final episode, the Ginga Reppu Unit was wiped out as it charged in bike form. Thus, while the protagonists were completely defeated, the "Bakushinger" was not defeated, making this the main mecha's unique ending in two senses.