Hirobo HI0404509 SX bevel pinion gear set compatible with Eagle/Freya/EX/SX helicopters  [HI0404509]

Gearset description and fitment

This Hirobo HI0404509 SX bevel pinion gear set serves as a replacement for the common components used on Eagle, Freya, EX and SX helicopter models. It operates as the driven/driving interface on the motor-to-gearbox axis and is supplied as a matched pair to ensure proper engagement where bevel pinions are employed.

Fitment is determined by model references and intended product application; the set is made to match the typical mounting patterns and shaft diameters found across Eagle/Freya/EX/SX parts. Do not assume compatibility with other frames without verifying shaft size and spline count from vendor information or original diagrams.

Setup and maintenance guidance: align the pinion teeth so faces are parallel, set a small but nonzero backlash, confirm smooth free rotation by hand, and verify alignment with any connected spur or bevel gears. Use a light gear lubricant on teeth after initial run-in and recheck mesh following a short test run. Proper pinion fitment helps maintain drivetrain timing and minimizes noise from worn or mismatched gears.

Fit this matched set as a service replacement while troubleshooting drivetrain faults on compatible Hirobo helicopters, and always confirm physical measurements before fitting.