The pass rate is the MOT first-time pass: a roadworthiness check of the items an MOT covers (brakes, lights, tyres, steering, structure, emissions), not a full mechanical inspection of engine or gearbox internals. It is a reliability signal, not a complete measure of mechanical reliability. What this measures.
“vs expected” adjusts for age, mileage and test class, so a cherished classic and a hard-used commuter are compared fairly. How this works.
What fails on a B50
| Component group | Share of defects | Defects | % of defects |
|---|---|---|---|
| lighting and signalling |
|
5 | 35.7 |
| brakes |
|
3 | 21.4 |
| steering and suspension |
|
3 | 21.4 |
| fuel and exhaust |
|
2 | 14.3 |
| driving controls |
|
1 | 7.1 |
Defects recorded against failed normal tests, 2005–2025, grouped by DVSA inspection section. One test can record multiple defects.
How rivals compare
On first-time pass rate the B50 beats 4 of its 4 closest rivals (KAWASAKI ZX-6R, SUZUKI GSF600, YAMAHA FZS600).
Rivals share this bike's type and sit within ±30% of its engine capacity, ≥ 5,000 tests. Card colour = better/worse first-time pass rate than the B50.
Compare with any bike
More BSA models
Pass rate by registration year
Best year to buy used: 1971 (93.0% pass). Weakest: 1971 (93.0%).
First-time pass rate by the year each bike was first registered (cohorts with ≥ 50 tests). Older cohorts are survivors: the worst examples have already left the road, which tends to lift the earliest years.
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