Input Shaft (Mainshaft) Speed Sensor Replacement

Do the battery removal procedure (see BATTERY REMOVAL AND INSTALLATION )
Disconnect the input shaft (mainshaft) speed sensor connector, and remove the input shaft (mainshaft) speed sensor (A)

Fig 1: Input Shaft (Mainshaft) Speed Sensor And O-Ring With Torque Specification
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Install a new O-ring (B) on a new input shaft (mainshaft) speed sensor, then install the input shaft (mainshaft) speed sensor
Check the connector for rust, dirt, or oil, then connect the connector securely
Do the battery installation procedure (see BATTERY REMOVAL AND INSTALLATION )