Triumph Bonneville L: MOT pass rate by registration year

Which Bonneville L years pass first time, and which fall short of the model's 88.0% average, from 1,057 DVSA tests.

1981

highest-passing year · 90.5%

1980

lowest-passing year · 82.4%

8.1pp

spread across 6 years

Pass rate by registration year

first-time pass rate · cohorts with 50 or more tests · registration year from first use date

Highest pass rate: 1981 (90.5% of 63 tests). Lowest: 1980 (82.4% of 119). Years more than two points below the model average: 1971, 1979, 1980.

Registered	Tests	First-time pass	vs model (88.0%)
1971	53	84.9%	-3.1 pp
1977	76	88.2%	+0.2 pp
1978	125	89.6%	+1.6 pp
1979	101	83.2%	-4.8 pp
1980	119	82.4%	-5.6 pp
1981	63	90.5%	+2.5 pp

Older cohorts are survivors: the worst examples have already left the road, which tends to lift the earliest years. A first-time MOT pass is a roadworthiness check, not a full mechanical inspection.

Pass rate over time

first-time pass rate by test year · 2006–2018

Questions

Which Bonneville L years have the lowest MOT pass rate?: 1971, 1979, 1980 registered examples pass first time less often than the Triumph Bonneville L overall (88.0%); the 1980 cohort is lowest at 82.4% from 119 tests.
Which Bonneville L year has the highest MOT pass rate?: 1981, at 90.5% of 63 first tests (2005–2025).
How much does the Bonneville L pass rate vary by year?: 8.1 percentage points between the highest (1981, 90.5%) and lowest (1980, 82.4%) cohorts with at least 50 tests. Older cohorts are survivors: the worst examples have already left the road, which tends to lift the earliest years.

Full report: Triumph Bonneville L reliability, failures and mileage · ranked #1604 of 5428 models· other Triumph models: Bonneville, Tiger, Sprint, Daytona, Speed Triple, Thunderbird