BSA B40

350cc Petrol Class 2

#775 of 5426 overall #36 of 62 BSAs #471 of 2787 other bikes

90.6%

first-time pass rate

3.5%

failed outright

8,069

median miles at test

3,360

MOT tests, 2005–2025

Pass rate over time

first-time pass rate by test year · 2005–2018

The B40's first-time pass rate has fallen 3.1 points since 2005, 98.3% to 95.2%.

Pass rate by mileage

how the B40's first-time pass rate falls with the odometer · class average 84.9%

A low-mileage B40 passes first time 91.2% of the time; by 50k that's 90.2%.

First-time pass rate by odometer reading at test, 10,000-mile bands for this model. Mileage is the strongest reliability signal. See the full curve.

What fails on a B40

failure defects by component group · advisories excluded

Component group	Defects	% of defects	vs all bikes
steering and suspension	90	31.9	0.6×
lighting and signalling	86	30.5	0.4×
tyres and wheels	37	13.1	0.4×
brakes	30	10.6	0.2×
body and structure	10	3.5	0.6×
drive system	9	3.2	0.4×
fuel and exhaust	8	2.8	0.3×
driving controls	5	1.8	0.6×
Items Not Tested	4	1.4	1.3×
reg plates and vin	3	1.1	0.1×

Defects recorded against failed normal tests, 2005–2025, grouped by DVSA inspection section. One test can record multiple defects. "vs all bikes" is how often this model's tests record a defect in the group, as a multiple of the all-bike rate.

How rivals compare

same type, similar capacity, high test volume

On first-time pass rate the B40 beats 4 of its 4 closest rivals (SUZUKI AN400, SUZUKI DR-Z400S, YAMAHA RD350).

SUZUKI AN400 86.2% pass · 27.1k tests SUZUKI DR-Z400S 80.4% pass · 26.8k tests YAMAHA RD350 86.3% pass · 19.6k tests KAWASAKI ZXR400 73.1% pass · 14.2k tests

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 B40.

Pass rate by registration year

how each model-year cohort fares · registration year from first use date

Best year to buy used: 1969 (95.7% pass). Weakest: 1968 (85.7%).

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.

BSA B40 FAQ

answers computed from the data above · terms in the glossary

Is the BSA B40 reliable?

The BSA B40 is more reliable than average for its class: 90.6% of its 3,360 MOT tests (2005–2025) passed first time, against a class average of 84.9%. That ranks it #775 of 5426 models.

What does a B40 fail its MOT on most?

steering and suspension — 32% of all defects recorded against failed B40 tests.

What is the best year of B40 to buy used?

By first-time pass rate, 1969-registered examples do best (95.7%) and 1968 worst (85.7%). Condition and history still trump the year.

How many miles will a B40 last?

The median B40 shows 8,069 miles at test, and examples around 50k miles still pass 90.2% of the time — mileage alone rarely kills one.