The TX-500 and 750 were abysmal failures and were discontinued in 1975. Yamaha still believed that a particular range needed a common prefix and, wanting the world to forget about the TXs, returned to XS. Thus, what would have been the TX-650B was instead the XS-650B and the XS range grew to include bikes from 250 to 1,100cc. Confused? The XS-650B of ’75 was much the same as the TX-A.