Hatroi HA215 Flange for #643 #644 and YS4C-63~70 OS4C-70~81 Engine Shaft Spare  [HA215]

RC engine shaft flange replacement

This Hatroi HA215 flange is an RC-scale accessory made to replace the specific reference part codes and engine listings. It is intended for use with #643, #644 and engines identified as YS4C-63~70 and OS4C-70~81, matching the fitment information shown in the product name.

Install this flange when a damaged or worn unit needs replacing to restore proper shaft engagement. The part helps preserve concentric mounting between the engine shaft and prop or coupling systems, and it is meant solely for correct mechanical connection and alignment on model glow engines.

Installation notes: confirm the flange seating face and fastener hole pattern match the original, clean mating surfaces before reassembly, and torque bolts to the values recommended by your engine or model manual. After fitting, check axial alignment to ensure the shaft turns true before normal use.

Tuning role: a fresh flange can reduce shaft runout and vibration at model scale, which improves the ability to assess throttle response and idle stability during engine setup and running checks.