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 DD's first-time pass rate has fallen 2.7 points since 2017, 71.8% to 69.1%.
What fails on a DD
| Component group | Share of defects | Defects | % of defects | vs all bikes |
|---|---|---|---|---|
| lamps and reflectors |
|
340 | 31.9 | 7.2× |
| brakes |
|
179 | 16.8 | 1.5× |
| structure and attachments |
|
150 | 14.1 | 8.9× |
| suspension |
|
89 | 8.4 | 5.4× |
| tyres |
|
88 | 8.3 | 5.0× |
| lighting and signalling |
|
73 | 6.9 | 0.5× |
| steering |
|
71 | 6.7 | 7.4× |
| steering and suspension |
|
27 | 2.5 | 0.4× |
| Identification of the vehicle |
|
25 | 2.3 | 5.8× |
| drive system |
|
23 | 2.2 | 1.6× |
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 DD beats 0 of its 4 closest rivals (YAMAHA YBR 125, HONDA CG125, HONDA CBF125).
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 DD.
Compare with any bike
More AJS models
Pass rate by registration year
Best year to buy used: 2012 (78.8% pass). Weakest: 2014 (63.2%).
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.
AJS DD FAQ
Is the AJS DD reliable?
The AJS DD is less reliable than average for its class: 68.4% of its 1,798 MOT tests (2005–2025) passed first time, against a class average of 73.4%. That ranks it #4831 of 5428 models.
What does a DD fail its MOT on most?
lamps and reflectors — 32% of all defects recorded against failed DD tests.
What is the best year of DD to buy used?
By first-time pass rate, 2012-registered examples do best (78.8%) and 2014 worst (63.2%). Condition and history still trump the year.
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