BIKERELIABILITY Reg check
League table/ BSA/B33
Model report · 2005–2025

BSA B33

500cc Petrol Class 2
#507 of 5428 overall #22 of 62 BSAs #312 of 2788 other bikes
91.8%
first-time pass rate
2.9%
failed outright
11,130
median miles at test
1,121
MOT tests, 2005–2025

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.

Pass rate over time

first-time pass rate by test year · 2005–2015

The B33's first-time pass rate has fallen 5.4 points since 2005, 92.5% to 87.1%.

80%89%97%2005: 92.5% pass (40 tests)2006: 93.0% pass (143 tests)2007: 93.6% pass (141 tests)2008: 94.6% pass (130 tests)2009: 93.6% pass (125 tests)2010: 90.8% pass (130 tests)2011: 91.9% pass (135 tests)2012: 92.5% pass (120 tests)2013: 83.3% pass (30 tests)2015: 87.1% pass (31 tests)20052015

Pass rate by mileage

how the B33's first-time pass rate falls with the odometer · class average 84.9%

A low-mileage B33 passes first time 92.7% of the time; by 50k that's 88.6%.

86%92%98%0k: 92.7% pass (522 tests)10k: 87.6% pass (177 tests)20k: 95.9% pass (74 tests)30k: 95.2% pass (105 tests)40k: 92.7% pass (82 tests)50k: 88.6% pass (44 tests)0k30k50k

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 B33

failure defects by component group · advisories excluded
Component group Share of defects Defects % of defects vs all bikes
lighting and signalling
33 44.6 0.3×
steering and suspension
14 18.9 0.3×
brakes
11 14.9 0.2×
tyres and wheels
9 12.2 0.4×
fuel and exhaust
2 2.7 0.2×
lamps and reflectors
1 1.4 0.1×
body and structure
1 1.4 0.2×
drive system
1 1.4 0.1×
Items Not Tested
1 1.4 1.0×
suspension
1 1.4 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 B33 beats 4 of its 4 closest rivals (KAWASAKI ZX-6R, SUZUKI GSF600, YAMAHA FZS600).

KAWASAKI ZX-6R 78.1% pass · 174k tests Compare head-to-head →
SUZUKI GSF600 77.3% pass · 143k tests Compare head-to-head →
YAMAHA FZS600 82.6% pass · 137k tests Compare head-to-head →
SUZUKI SV650S 80.6% pass · 84.6k tests Compare head-to-head →

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 B33.

Compare with any bike

rival not listed above? pick any model to see it head-to-head with the B33

More BSA models

other BSA bikes ranked by MOT pass rate
BSA A10 91.6% pass · 10.2k tests
BSA BANTAM 88.7% pass · 7,202 tests
BSA C15 89.2% pass · 5,895 tests
BSA A65 90.9% pass · 5,064 tests
BSA B31 92.0% pass · 3,429 tests
BSA B40 90.6% pass · 3,360 tests

See all BSA models →

Pass rate by registration year

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

Best year to buy used: 1960 (97.4% pass). Weakest: 1957 (87.3%).

85%92%99%1949: 91.8% pass (73 tests)1950: 96.6% pass (59 tests)1954: 94.1% pass (136 tests)1955: 95.2% pass (124 tests)1956: 91.3% pass (103 tests)1957: 87.3% pass (79 tests)1958: 88.2% pass (93 tests)1959: 90.4% pass (115 tests)1960: 97.4% pass (77 tests)194919561960

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 B33 FAQ

answers computed from the data above · terms in the glossary

Is the BSA B33 reliable?

The BSA B33 is more reliable than average for its class: 91.8% of its 1,121 MOT tests (2005–2025) passed first time, against a class average of 84.9%. That ranks it #507 of 5428 models.

What does a B33 fail its MOT on most?

lighting and signalling — 45% of all defects recorded against failed B33 tests.

What is the best year of B33 to buy used?

By first-time pass rate, 1960-registered examples do best (97.4%) and 1957 worst (87.3%). Condition and history still trump the year.

How many miles will a B33 last?

The median B33 shows 11,130 miles at test, and examples around 50k miles still pass 88.6% of the time — mileage alone rarely kills one.

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