The invention relates to a bearing housing body group (1) of an exhaust-gas turbocharger, having a housing (2) for a bearing arrangement of a rotor shaft (3); having a turbine wheel (4) on one end (5) of the rotor shaft (3); having a compressor wheel (6) on the opposite end (7) of the rotor shaft (3); and having a compressor-wheel-side housing cover (8) which can be fixed by means of a fastening device (9) in a compressor-wheel-side housing opening (10), wherein the fastening device (9) is designed as a bayonet connection.