| MODEL | BSA A65 LIGHTNING 650 1971 |
| Year | 1971 |
| Engine Type | Four stroke, parallel twin cylinder, OHV |
| Displacement / Capacity | 654 cc / 39.9 cu in |
| Bore X Stroke | 75 x 74 mm |
| Compression Ratio | 9.0:1 |
| Cooling System | — |
| Max Power | 38.7 kW / 52 hp @ 7000 rpm |
| Max Torque | 52.8 Nm / 39 lb-ft @ 5750 rpm |
| Ignition | Battery coil |
| Induction | — |
| Start System | — |
| TRANSMISSION SPECS | |
| Lubrication | — |
| Gear Box | — |
| Clutch | Multi-disc wet |
| Final Drive | Chain |
| CHASSIS SPECS | |
| Frame | Steel tubing, cradle |
| Front Suspension | Telescopic forks with coil spring, hydraulically damped |
| Rear Suspension | Coil spring / hydraulically damped, swinging arm |
| Front Brakes | 203 mm / 8 in, drum |
| Rear Brakes | 178 mm / 7 in, drum |
| DIMENSION SPECS | |
| Overall Length | — |
| Overall Width | — |
| Overall Height | — |
| Seat Height | 825.5 mm / 32.5 in |
| Wheelbase | 1435 mm / 56.5 in |
| Ground Clearance | 171.4 mm / 6.75 in |
| Dry Weight | — |
| Wet Weight | 190.5 kg / 420 lb |
| WHEEL SPECS | |
| Front Tyre | 3.25 x 19 in |
| Rear Tyre | 4.00 x 18 in |
| FUEL SYSTEM | |
| Fuel Capacity | 11.4 Litres / 3 US gal |
| Fuel Consumption | — |
| Top Speed | — |
For 1971 the Lightning received a new frame in an effort to extend the model's life. The sports 650 engine stayed essentially the same, but the new frame raised the seat height. It was one of the last versions before BSA's twin range ended.
