| MODEL | HONDA CB 750 FOUR PROTOTYPE 1968 |
| Year | 1968 |
| Engine Type | Four stroke, transverse four cylinder, SOHC, 2 valves per cylinder |
| Displacement / Capacity | 736 cc / 44.9 cu in |
| Bore X Stroke | 61 x 63 mm |
| Compression Ratio | 9.0:1 |
| Cooling System | Air cooled |
| Max Power | 50 kW / 67 hp @ 8000 rpm |
| Max Torque | 60 Nm / 44 lb-ft @ 7000 rpm |
| Ignition | Battery, coils |
| Induction | 4 x 28 mm Keihin carburetors |
| Start System | Electric and kick |
| TRANSMISSION SPECS | |
| Lubrication | Dry sump |
| Gear Box | 5 speed |
| Clutch | Multi-plate, wet |
| Final Drive | Chain |
| CHASSIS SPECS | |
| Frame | Tubular steel duplex cradle |
| Front Suspension | Telescopic fork, non-adjustable |
| Rear Suspension | Swingarm, dual shocks, preload adjustable |
| Front Brakes | Single 296 mm disc |
| Rear Brakes | 179 mm drum |
| DIMENSION SPECS | |
| Overall Length | — |
| Overall Width | — |
| Overall Height | — |
| Seat Height | 800 mm / 31.5 in |
| Wheelbase | 1453 mm / 57.2 in |
| Ground Clearance | 160 mm / 6.3 in |
| Dry Weight | — |
| Wet Weight | 226 kg / 499 lbs |
| WHEEL SPECS | |
| Front Tyre | 3.25-19 |
| Rear Tyre | 4.00-18 |
| FUEL SYSTEM | |
| Fuel Capacity | 18.2 Litres / 4.8 US gal |
| Fuel Consumption | 6.9 L/100 km / 14.6 km/l / 34.3 US mpg |
| Top Speed | 198 km/h / 123.2 mph |
Before the CB750 went on sale Honda hand-built a small number of pre-production prototypes, and the machine was revealed at the Tokyo Motor Show late in 1968. The bike featured on this page is a surviving California-based prototype, restored with a CB450-style fuel tank and Candy blue-green paint, with details that sit between the show prototype and the first production K0.
