Data as of: DVSA MOT results to 2025
HONDA CB400 FOUR
The pass rate is the MOT first-time pass: a roadworthiness check of the items an MOT covers (brakes, lights, tyres, steering, structure, emissions), not a full mechanical inspection of engine or gearbox internals. It is a reliability signal, not a complete measure of mechanical reliability. What this measures.
“vs expected” adjusts for age, mileage and test class, so a cherished classic and a hard-used commuter are compared fairly. How this works.
Pass rate over time
The CB400 FOUR's first-time pass rate has fallen 7.9 points since 2006, 84.4% to 76.5%.
Pass rate by mileage
A low-mileage CB400 FOUR passes first time 86.0% of the time; by 50k that's 72.4%.
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 CB400 FOUR
| Component group | Share of defects | Defects | % of defects | vs all bikes |
|---|---|---|---|---|
| lighting and signalling |
|
64 | 34 | 1.1× |
| brakes |
|
48 | 25.5 | 0.9× |
| steering and suspension |
|
31 | 16.5 | 0.8× |
| tyres and wheels |
|
15 | 8 | 0.6× |
| fuel and exhaust |
|
7 | 3.7 | 1.0× |
| body and structure |
|
6 | 3.2 | 1.1× |
| driving controls |
|
5 | 2.7 | 2.3× |
| drive system |
|
5 | 2.7 | 0.7× |
| reg plates and vin |
|
4 | 2.1 | 0.7× |
| lamps and reflectors |
|
3 | 1.6 | 0.2× |
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
On first-time pass rate the CB400 FOUR beats 2 of its 3 closest rivals (HONDA CB500, HONDA CB400, HONDA CB400N).
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 CB400 FOUR.
Compare with any bike
More HONDA models
Pass rate by registration year
Highest pass rate: 1975 (86.6%). Lowest: 1978 (82.4%). Every CB400 Four year compared →
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.
HONDA CB400 FOUR FAQ
Is the HONDA CB400 FOUR reliable?
The HONDA CB400 FOUR is about average for its class: 83.2% of its 945 MOT tests (2005–2025) passed first time, against a class average of 84.9%. That ranks it #2911 of 5428 models.
What does a CB400 FOUR fail its MOT on most?
lighting and signalling: 34% of all defects recorded against failed CB400 FOUR tests.
What is the best year of CB400 FOUR to buy used?
By first-time pass rate, 1975-registered examples do best (86.6%) and 1978 worst (82.4%). Condition and history still trump the year.
How many miles will a CB400 FOUR last?
The median CB400 FOUR shows 31,108 miles at test, and examples around 50k miles still pass 72.4% of the time, so mileage alone rarely decides the result.
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