| MODEL | HONDA CB 650 1981 |
| Year | 1981 |
| Engine Type | Four stroke, transverse four cylinder, SOHC, 2 valves per cylinder |
| Displacement / Capacity | 626.8 cc / 38.2 cu in |
| Bore X Stroke | 59.8 x 55.8 mm |
| Compression Ratio | 9.0:1 |
| Cooling System | Air cooled |
| Max Power | 46.9 kW / 63 hp @ 9000 rpm |
| Max Torque | 51.5 Nm / 38 lb-ft @ 8000 rpm |
| Ignition | Transistorised |
| Induction | 4 x 26 mm Keihin carburettors |
| Start System | Electric |
| TRANSMISSION SPECS | |
| Lubrication | — |
| Gear Box | 5 Speed |
| Clutch | — |
| Final Drive | Chain |
| CHASSIS SPECS | |
| Frame | — |
| Front Suspension | Centre-axle coil spring forks, 135 mm / 5.3 in travel |
| Rear Suspension | Dual Showa dampers, adjustable spring preload, 91 mm / 3.5 in travel |
| Front Brakes | Single 275 mm disc, 1-piston caliper |
| Rear Brakes | 180 mm drum |
| DIMENSION SPECS | |
| Overall Length | — |
| Overall Width | — |
| Overall Height | — |
| Seat Height | — |
| Wheelbase | — |
| Ground Clearance | — |
| Dry Weight | — |
| Wet Weight | 212 kg / 467.3 lbs |
| WHEEL SPECS | |
| Front Tyre | 3.50-19 |
| Rear Tyre | 4.50-17 |
| FUEL SYSTEM | |
| Fuel Capacity | 18 Litres / 4.7 US gal |
| Fuel Consumption | 41.1 mpg (US) |
| Top Speed | 190 km/h / 118 mph |
The 1981 CB650 standard carried on largely unchanged: the same 627 cc SOHC eight-valve four, five-speed gearbox, chain drive and twin rear shocks. It remained Honda's no-frills middleweight four while the Custom version took the styling changes.
