Harley-Davidson Model W Sport Twin vs BSA M 21 (1956)
Side-by-side spec comparison, pricing, and a plain-English breakdown of how the Harley-Davidson Model W Sport Twinstacks up against the BSA M 21. Numbers pulled from manufacturer spec sheets — click either bike for the full review.
Spec comparison
| Spec | Harley-Davidson Model W Sport Twin | BSA M 21 |
|---|---|---|
| Model year | 1924 | 1956 |
| Price | — | — |
| Engine | 584 cc | 591 cc |
| Horsepower | — | 15 hp |
| Weight | 113 kg | — |
| Fuel capacity | — | 3.0 L |
| Fuel type | petrol | petrol |
| Front brakes | — | Expanding brake (drum brake) |
| Rear brakes | — | Expanding brake (drum brake) |
| Tires | 3-26 / 3-26 | 3.25-19 / 3.25-19 |
Harley-Davidson Model W Sport Twin vs BSA M 21 — which should you buy?
Picking between the Harley-Davidson Model W Sport Twin and the BSA M 21 usually comes down to the numbers you care about most. On paper, the Harley-Davidson Model W Sport Twin brings its published horsepower in a 113 kg package, while the BSA M 21 counters with 15 hp.
Our spec tables above highlight the winning number on each line. For the full rider-focused reviews including real-world fuel economy, service costs and available colors, click into either bike: