Hirobo HI0304161 Replacement Main Mast Lock for EMBLA EB  [HI0304161]

Replacement main mast lock for EMBLA EB models

This replacement main mast lock fits EMBLA EB helicopters and is listed as Hirobo part number HI0304161. It acts as the retention device that secures the main mast to the rotor assembly on EMBLA EB scale models and is intended for hobby use.

In workshop practice the lock keeps the mast steady while you carry out routine servicing and preflight inspections — for example when checking the rotor head, swapping bearings, or performing alignment. It is offered as a direct replacement when the factory lock wears or allows play.

Fitting usually occurs during rotor head removal or rebuild; the lock mates with the mast seating and retention points and helps maintain mast stability while you make adjustments to swash geometry, confirm tracking, or balance blades.