RC Shaft Alignment Flange Hatroi HA215 for #643 #644 YS4C-63~70 OS4C-70~81  [HA215]

Model engine flange for shaft alignment

The Hatroi HA215 flange functions as a precision RC-scale replacement for the referenced part numbers and engine series. It is matched for use with #643, #644 and engines identified as YS4C-63~70 and OS4C-70~81, maintaining the fitment references listed in the product name.

Fit this flange when a worn or damaged flange is affecting shaft engagement. The component helps keep the engine shaft concentric with props or couplings and is intended for correct mechanical alignment on model glow engines only.

Installation notes: verify the flange seating face and bolt pattern align with the original, clean mating surfaces prior to reassembly, and fasten to recommended torque values from your engine or model manual. After installation, inspect axial alignment to confirm the shaft runs true before extended operation.

Tuning role: upgrading a degraded flange often reduces runout and vibration, improving the clarity of throttle response and idle behavior during engine tuning and track checks.