Bafang Mid Drive Motor Kit. Bafang 48V 750W Mid Drive Motor 17.5Ah 20Ah EBike Mountain Bike Conversion Kits. Electric Bike Part Speed Sensor for BAFANG BBS01 BBS02 BBSHD Mid Drive Motor Kit. This motor is the newest BAFANG version BBS01B/BBS02B, with the gear sensor & light function.