Based on the serial number, I'm guessing it's a 1974 (August), although it could be a 1984.

From Schwinn Bulletin 23, "Schwinn Bicycle Identification Numbers":

Bicycles from Japan have a production month letter in either the first or second position and a production year number in the other (first or second) position. Examples J677123 = September, 1976, 6J77123 = September, 1976.

Are the graphics like this?