Data as of: DVSA MOT results to 2025
Ajs Tempest Roadster vs Yamaha YBR 125
The Ajs Tempest Roadster passes its MOT first time more often than the Yamaha YBR 125: 72.2% vs 71.0%, a 1.2-point lead.
MOT reliability, side by side
| Metric | Ajs Tempest Roadster | Yamaha YBR 125 |
|---|---|---|
| First-time pass rate | 72.2% | 71.0% |
| Outright fail rate | 18.3% | 17.1% |
| Vs comparable bikes (age & mileage adjusted) | -4.1 pts | -1.1 pts |
| Engine size | 124cc | 124cc |
| Rank among all models | #4568 of 5428 | #4664 of 5428 |
| Median miles at test | 3,790 | 10,652 |
| MOT tests analysed | 558 | 124,897 |
| Most common failure | brakes | brakes |
First-time outcomes on normal tests, 2005–2025. "Most common failure" is the component group with the most recorded defects on failed tests. Read pass rates against test counts: a smaller sample is noisier. Source: DVSA anonymised MOT results.
"Vs comparable bikes" is the first-time pass rate minus the rate expected for each bike's own mix of age, mileage and test class, in percentage points: positive means better than comparable bikes. How this works.
What fails, side by side
| Component | Ajs Tempest Roadster | Yamaha YBR 125 |
|---|---|---|
| Lights & signalling | 9.3% | 8.5% |
| Brakes | 10.4% | 5.9% |
| Steering & suspension | 5.4% | 6.5% |
| Structure & body | 4.1% | 3.8% |
| Tyres & wheels | 0.2% | 4.4% |
| Drive system | 0% | 2.9% |
| Fuel & exhaust | 0% | 0.6% |
A test that fails on two components counts once in each. Component links go to the bikes most likely to fail on it.
Pass rate by test year
| Test year | Ajs Tempest Roadster | Yamaha YBR 125 |
|---|---|---|
| 2021 | 86.0% | 71.6% |
| 2022 | 72.4% | 71.3% |
| 2023 | 65.6% | 71.1% |
| 2024 | 68.4% | 70.9% |
| 2025 | 74.8% | 71.2% |
Each year mixes bikes of different ages, so a fleet that is getting older tends to slip.
Pass rate by mileage
| Mileage | Ajs Tempest Roadster | Yamaha YBR 125 |
|---|---|---|
| 0k-10k miles | 75.1% | 76.8% |
| 10k-20k miles | 59.7% | 67.4% |
Bands with fewer than 30 tests for either bike are left out.
Ajs Tempest Roadster vs Yamaha YBR 125 FAQ
Which is more reliable, the Ajs Tempest Roadster or the Yamaha YBR 125?
The Ajs Tempest Roadster passes its MOT first time more often than the Yamaha YBR 125: 72.2% vs 71.0%, a 1.2-point lead. Adjusted for age, mileage and test class, the Yamaha YBR 125 still comes out ahead: -4.1 points vs comparable bikes for the Ajs Tempest Roadster, -1.1 for the Yamaha YBR 125. An MOT checks roadworthiness items, not engine or gearbox internals.
What does the Ajs Tempest Roadster fail its MOT on most?
Brakes: 10.4% of Ajs Tempest Roadster MOT tests failed on it, then lights & signalling (9.3%).
What does the Yamaha YBR 125 fail its MOT on most?
Lights & signalling: 8.5% of Yamaha YBR 125 MOT tests failed on it, then steering & suspension (6.5%).
See each bike's full report (trend, mileage curve, failure breakdown and rivals) on its own page.