Lambretta SX150: MOT pass rate by registration year

Which SX150 years pass first time, and which fall short of the model's 89.7% average, from 3,964 DVSA tests.

1970

highest-passing year · 95.1%

1966

lowest-passing year · 87.7%

7.4pp

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: 1970 (95.1% of 81 tests). Lowest: 1966 (87.7% of 494).

Registered	Tests	First-time pass	vs model (89.7%)
1966	494	87.7%	-2.0 pp
1967	1,574	89.0%	-0.7 pp
1968	1,186	89.9%	+0.2 pp
1969	354	91.2%	+1.5 pp
1970	81	95.1%	+5.4 pp
1971	54	94.4%	+4.7 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 · 2005–2021

Questions

Which SX150 years have the lowest MOT pass rate?: none: no registration year of the Lambretta SX150 falls more than two points under the model's 89.7% overall pass rate.
Which SX150 year has the highest MOT pass rate?: 1970, at 95.1% of 81 first tests (2005–2025). Years more than two points above the model average: 1970, 1971.
How much does the SX150 pass rate vary by year?: 7.4 percentage points between the highest (1970, 95.1%) and lowest (1966, 87.7%) 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: Lambretta SX150 reliability, failures and mileage · ranked #1049 of 5428 models· other Lambretta models: LI125, GP200, LI150, GP150, GP125, Li