Zius BK1S/BK2S Gearbox with Motor Cage

This is the complete replacement gearbox for the Zius BK1S and BK2S, sold as a full assembly rather than a bare shell — the motor cage, trigger, and trigger spring are all included, so you're not left hunting for the small parts that usually go missing when a gearbox gets stripped for repair. It's the part to reach for when your existing gearbox has worn internals, damaged gears, or you simply want a known-good unit to drop in without troubleshooting individual components.

Because it's built specifically for the BK1S/BK2S platform, fitment is straightforward: pull the old gearbox, transfer over your motor, and the new set is ready to go. It's also a sensible option to keep on hand as a spare if you rely on your BK1S or BK2S for regular play and can't afford downtime.