I also noticed in one of my early CB750 Owners Manual (printed in February 1970), showing many rare photos of the 1968 prototype displayed in that January 1969 Cycle World issue with a touch-up side cover drawing depicting the production model. It's also little humorous to see a funny looking kill switch drawn in (the prototype had no kill switch) that don't look anything like the production version. It's important to note that both CB750 demonstrator (shown in December 1968 Cycle World) and the first prototype CB750 (shown in Motorcycle Collector Magazine V1#4), both with CB450 drum brakes, had single throttle cable while the second CB750 prototype shown in 1968 Tokyo motor show, then in March 1969 issue of Cycle Guide, had dual throttle cables, but the first pre-production CB750, shown in England in April 1969, with prototype front disc unit, reverted back to the cheaper single throttle cable system.