| MODEL | BSA S29 OHV TWIN-PORT 500 1929 |
| Year | 1929 |
| Engine Type | Inclined single-cylinder four-stroke overhead-valve, two-port head |
| Displacement / Capacity | — |
| Bore X Stroke | 80 mm x 98 mm |
| Compression Ratio | Low-compression piston standard, high-compression optional (ratio not given) |
| Cooling System | — |
| Max Power | 4.93 hp (rating) |
| Max Torque | — |
| Ignition | — |
| Induction | Amac TT carburettor |
| Start System | — |
| TRANSMISSION SPECS | |
| Lubrication | 3-pint integral sump, submerged gear pump with tell-tale |
| Gear Box | BSA gearbox on special pivot, close or wide ratio optional |
| Clutch | — |
| Final Drive | Chain: front 1/2 x 0.305 in, rear 5/8 x 3/8 in |
| CHASSIS SPECS | |
| Frame | Duplex cradle frame with steering damper |
| Front Suspension | — |
| Rear Suspension | — |
| Front Brakes | 7 in, taper roller hub bearings |
| Rear Brakes | 7 in, quickly adjustable |
| DIMENSION SPECS | |
| Overall Length | — |
| Overall Width | — |
| Overall Height | — |
| Seat Height | — |
| Wheelbase | — |
| Ground Clearance | — |
| Dry Weight | — |
| Wet Weight | — |
| WHEEL SPECS | |
| Front Tyre | 26 x 3.25 in Dunlop cord wired-on |
| Rear Tyre | 26 x 3.25 in Dunlop cord wired-on |
| FUEL SYSTEM | |
| Fuel Capacity | — |
| Fuel Consumption | — |
| Top Speed | — |
The twin-port S29 was the sporting version of the BSA sloper overhead-valve 500, fitted with a two-port head, an Amac TT carburettor and a reversible sports handlebar. It was the road-going relation of the dirt-track engine of the same year.
