BSA THUNDERBOLT

650cc Petrol Class 2

#618 of 5426 overall #30 of 62 BSAs #376 of 2787 other bikes

91.3%

first-time pass rate

2.8%

failed outright

14,618

median miles at test

1,094

MOT tests, 2005–2025

Pass rate over time

first-time pass rate by test year · 2006–2017

The THUNDERBOLT's first-time pass rate has risen 1.4 points since 2006, 89.3% to 90.7%.

Pass rate by mileage

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

A low-mileage THUNDERBOLT passes first time 89.9% of the time; by 40k that's 96.8%.

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 THUNDERBOLT

failure defects by component group · advisories excluded

Component group	Defects	% of defects	vs all bikes
steering and suspension	17	28.3	0.4×
brakes	13	21.7	0.2×
lighting and signalling	12	20	0.2×
body and structure	5	8.3	1.0×
tyres and wheels	4	6.7	0.2×
fuel and exhaust	3	5	0.4×
driving controls	2	3.3	0.8×
drive system	2	3.3	0.3×
Other	2	3.3	—

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 THUNDERBOLT beats 4 of its 4 closest rivals (KAWASAKI ZX-6R, SUZUKI GSF600, YAMAHA FZS600).

KAWASAKI ZX-6R 78.1% pass · 174k tests SUZUKI GSF600 77.3% pass · 143k tests YAMAHA FZS600 82.6% pass · 137k tests HONDA VFR800 FI 86.7% pass · 89.4k 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 THUNDERBOLT.

Pass rate by registration year

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

Best year to buy used: 1966 (97.0% pass). Weakest: 1972 (85.8%).

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 THUNDERBOLT FAQ

answers computed from the data above · terms in the glossary

Is the BSA THUNDERBOLT reliable?

The BSA THUNDERBOLT is more reliable than average for its class: 91.3% of its 1,094 MOT tests (2005–2025) passed first time, against a class average of 84.9%. That ranks it #618 of 5426 models.

What does a THUNDERBOLT fail its MOT on most?

steering and suspension — 28% of all defects recorded against failed THUNDERBOLT tests.

What is the best year of THUNDERBOLT to buy used?

By first-time pass rate, 1966-registered examples do best (97.0%) and 1972 worst (85.8%). Condition and history still trump the year.

How many miles will a THUNDERBOLT last?

The median THUNDERBOLT shows 14,618 miles at test, and examples around 40k miles still pass 96.8% of the time — mileage alone rarely kills one.