Data as of: DVSA MOT results to 2025
Yamaha DT50 vs Piaggio NRG
The Piaggio NRG passes its MOT first time more often than the Yamaha DT50: 65.5% vs 60.5%, a 5.0-point lead.
MOT reliability, side by side
| Metric | Yamaha DT50 | Piaggio NRG |
|---|---|---|
| First-time pass rate | 60.5% | 65.5% |
| Outright fail rate | 27.7% | 27.4% |
| Vs comparable bikes (age & mileage adjusted) | -13.8 pts | -6.0 pts |
| Engine size | 49cc | 49cc |
| Rank among all models | #5195 of 5428 | #4992 of 5428 |
| Median miles at test | 17,837 | 9,874 |
| MOT tests analysed | 2,974 | 40,458 |
| Most common failure | lighting and signalling | lighting and signalling |
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 | Yamaha DT50 | Piaggio NRG |
|---|---|---|
| Lights & signalling | 21.6% | 15.0% |
| Steering & suspension | 14.7% | 15.5% |
| Brakes | 9.1% | 10.2% |
| Tyres & wheels | 6.3% | 4.7% |
| Fuel & exhaust | 3.7% | 3.8% |
| Structure & body | 3.9% | 2.5% |
| Drive system | 6.2% | 0.0% |
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 | Yamaha DT50 | Piaggio NRG |
|---|---|---|
| 2018 | 70.3% | 69.2% |
| 2019 | 71.1% | 68.0% |
| 2020 | 64.5% | 71.8% |
| 2021 | 78.2% | 72.9% |
| 2022 | 71.8% | 74.8% |
| 2023 | 78.6% | 77.5% |
| 2024 | 75.4% | 81.9% |
| 2025 | 71.7% | 77.1% |
Each year mixes bikes of different ages, so a fleet that is getting older tends to slip.
Pass rate by mileage
| Mileage | Yamaha DT50 | Piaggio NRG |
|---|---|---|
| 0k-10k miles | 61.7% | 71.3% |
| 10k-20k miles | 60.0% | 60.6% |
| 20k-30k miles | 58.6% | 55.7% |
| 30k-40k miles | 64.6% | 57.0% |
| 40k-50k miles | 56.3% | 60.8% |
Bands with fewer than 30 tests for either bike are left out.
Yamaha DT50 vs Piaggio NRG FAQ
Which is more reliable, the Yamaha DT50 or the Piaggio NRG?
The Piaggio NRG passes its MOT first time more often than the Yamaha DT50: 65.5% vs 60.5%, a 5.0-point lead. Adjusted for age, mileage and test class, the Piaggio NRG still comes out ahead: -13.8 points vs comparable bikes for the Yamaha DT50, -6.0 for the Piaggio NRG. An MOT checks roadworthiness items, not engine or gearbox internals.
What does the Yamaha DT50 fail its MOT on most?
Lights & signalling: 21.6% of Yamaha DT50 MOT tests failed on it, then steering & suspension (14.7%).
What does the Piaggio NRG fail its MOT on most?
Steering & suspension: 15.5% of Piaggio NRG MOT tests failed on it, then lights & signalling (15.0%).
Which holds up better at high mileage, the Yamaha DT50 or the Piaggio NRG?
At 40k-50k miles the Piaggio NRG passes first time more often: 56.3% for the Yamaha DT50 vs 60.8% for the Piaggio NRG.
See each bike's full report (trend, mileage curve, failure breakdown and rivals) on its own page.