Honda CB400/4: MOT pass rate by registration year

Which CB400/4 years pass first time, and which fall short of the model's 84.8% average, from 1,426 DVSA tests.

1979

highest-passing year · 89.1%

1975

lowest-passing year · 82.3%

6.8pp

spread across 5 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: 1979 (89.1% of 92 tests). Lowest: 1975 (82.3% of 175). Years more than two points below the model average: 1975.

Registered	Tests	First-time pass	vs model (84.8%)
1975	175	82.3%	-2.5 pp
1976	383	87.5%	+2.7 pp
1977	449	83.7%	-1.1 pp
1978	241	83.8%	-1.0 pp
1979	92	89.1%	+4.3 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 CB400/4 years have the lowest MOT pass rate?: 1975 registered examples pass first time less often than the Honda CB400/4 overall (84.8%); the 1975 cohort is lowest at 82.3% from 175 tests.
Which CB400/4 year has the highest MOT pass rate?: 1979, at 89.1% of 92 first tests (2005–2025). Years more than two points above the model average: 1976, 1979.
How much does the CB400/4 pass rate vary by year?: 6.8 percentage points between the highest (1979, 89.1%) and lowest (1975, 82.3%) 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: Honda CB400/4 reliability, failures and mileage · ranked #2543 of 5428 models· other Honda models: CBR600F, CBR900RR, CBR1100XX, CB500, C90, VFR800 Fi