Honda CB400 Four: MOT pass rate by registration year

Which CB400 Four years pass first time, and which fall short of the model's 83.2% average, from 945 DVSA tests.

1975

highest-passing year · 86.6%

1978

lowest-passing year · 82.4%

4.2pp

spread across 4 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: 1975 (86.6% of 67 tests). Lowest: 1978 (82.4% of 153).

Registered	Tests	First-time pass	vs model (83.2%)
1975	67	86.6%	+3.4 pp
1976	277	83.4%	+0.2 pp
1977	250	84.4%	+1.2 pp
1978	153	82.4%	-0.8 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 Four years have the lowest MOT pass rate?: none: no registration year of the Honda CB400 Four falls more than two points under the model's 83.2% overall pass rate.
Which CB400 Four year has the highest MOT pass rate?: 1975, at 86.6% of 67 first tests (2005–2025).
How much does the CB400 Four pass rate vary by year?: 4.2 percentage points between the highest (1975, 86.6%) and lowest (1978, 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: Honda CB400 Four reliability, failures and mileage · ranked #2911 of 5428 models· other Honda models: CBR600F, CBR900RR, CBR1100XX, CB500, C90, VFR800 Fi