The black bike pictured a the beginning of this article is not a TX750, but is in fact a XS650. I have both seen many of these bikes, & have also owned an XS650,XS750 (3 cyl) TX750, XV750, & XJ750 (4 cyl) The Cyl head & trans on the TX750 looks totally different from any other Yamaha. Yamaha did produce a 750 twin (racing only) based on the XS650 engine, piloted by the superb Kenny Roberts, which acquitted itself well on the short tracks. Yamaha also made a 4 cyl 2 stroke water cooled 750 for superspeedway racing, which they also ran in a few short track races, also by Kenny Roberts. He later pronounced it too deadly to ride because of its outrageous power, & light switch powerband. Kenny said spinning the wheels in top gear coming off the Daytona banking was a little much even for him.