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 S4's first-time pass rate has risen 3.9 points since 2005, 87.0% to 90.9%.
Pass rate by mileage
A low-mileage S4 passes first time 87.5% of the time; by 40k that's 82.2%.
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 S4
| Component group | Share of defects | Defects | % of defects | vs all bikes |
|---|---|---|---|---|
| lighting and signalling |
|
252 | 37.8 | 0.9× |
| brakes |
|
87 | 13 | 0.4× |
| steering and suspension |
|
78 | 11.7 | 0.5× |
| tyres and wheels |
|
75 | 11.2 | 0.7× |
| lamps and reflectors |
|
55 | 8.2 | 0.5× |
| fuel and exhaust |
|
43 | 6.4 | 1.1× |
| reg plates and vin |
|
31 | 4.6 | 1.1× |
| drive system |
|
23 | 3.4 | 0.6× |
| structure and attachments |
|
13 | 1.9 | 0.4× |
| Identification of the vehicle |
|
10 | 1.5 | 1.0× |
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 S4 beats 1 of its 4 closest rivals (BMW R1200, BMW R1150, TRIUMPH SPRINT).
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 S4.
Compare with any bike
More DUCATI models
Pass rate by registration year
Best year to buy used: 2006 (94.0% pass). Weakest: 2004 (74.3%).
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.
DUCATI S4 FAQ
Is the DUCATI S4 reliable?
The DUCATI S4 is about average for its class: 84.5% of its 4,277 MOT tests (2005–2025) passed first time, against a class average of 84.9%. That ranks it #2613 of 5428 models.
What does a S4 fail its MOT on most?
lighting and signalling — 38% of all defects recorded against failed S4 tests.
What is the best year of S4 to buy used?
By first-time pass rate, 2006-registered examples do best (94.0%) and 2004 worst (74.3%). Condition and history still trump the year.
How many miles will a S4 last?
The median S4 shows 10,476 miles at test, and examples around 40k miles still pass 82.2% of the time — mileage alone rarely kills one.
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