The CB750 Timeline

Major changes in the history of the CB750

CB750K Model

Year Model Changes
1969 This is the original version of the CB750.  Notable differences from later models include louvered side panels, all-cable throttles, plastic instrument lenses and a duck-tail (humped) seat.  The first 7400 or so bikes had 'sand-cast' crankcases.
1971 Beam-operated throttles; re-styled airbox and oil tank with new emblems; white tank lettering; black front caliper.
1972 K2 with restricted silencers; altered rear shocks; metal chainguard; warning light panel between the instruments.
1973 K3 introduced in the US; K2 continues elsewhere.  Improved front forks and five-way adjustable shocks.  The K3 had new tank graphics, restricted air intake, front disc water guard, and running lights in the indicators.
1974 K4 for the US and Japan; K2 elsewhere.  Only 3 vertical braces in cylinder head side fins.  The K4 added a ratio indicator on the gearbox.
1975 K5 for the US; K2/K4 elsewhere.  The K5 got bigger indicators and a rubber-tipped flip-up side stand.
1976 K6 with stronger swing-arm; detuned engine; no chain oiler.
1977 K7 with F1-style engine and single carburettor accelerator pump; plainer silencers; 17 inch rear wheel with wider tire; O-ring chain; flush fuel filler.
1978 K8 for the US with two-tier seat; minor engine changes.

 

CB750F Model

Year Model Changes
1975/1976 F0/F1: changes from CB750K: lower gearing; 4-1 exhaust; increased fork trail; stronger swingarm; disc rear breake; "Euro" cosmetics
1977/1978 F2/F3: changes from F0/F1: Bigger valves and stronger bottom-end in 70bhp engine; accelerator pump; new front fork with twin brake disks; Comstar 5-spoke wheels; FVQ shocks

 

CB750A Model

Year Model Changes
1977 A1 (Japan: EARA); 4-2 exhaust
1978 A2; Comstar 5-spoke wheels