Data as of: DVSA MOT results to 2025
SYM AD12W Jet 4 125 vs Piaggio Vespa
The Piaggio Vespa passes its MOT first time more often than the SYM AD12W Jet 4 125: 80.7% vs 72.9%, a 7.8-point lead.
MOT reliability, side by side
| Metric | SYM AD12W Jet 4 125 | Piaggio Vespa |
|---|---|---|
| First-time pass rate | 72.9% | 80.7% |
| Outright fail rate | 19.8% | 12.2% |
| Vs comparable bikes (age & mileage adjusted) | +2.1 pts | +5.9 pts |
| Engine size | 124cc | 124cc |
| Rank among all models | #4508 of 5428 | #3439 of 5428 |
| Median miles at test | 12,309 | 10,023 |
| MOT tests analysed | 2,366 | 287,482 |
| Most common failure | brakes | 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 | SYM AD12W Jet 4 125 | Piaggio Vespa |
|---|---|---|
| Lights & signalling | 7.8% | 6.4% |
| Tyres & wheels | 8.1% | 3.8% |
| Brakes | 8.1% | 3.5% |
| Steering & suspension | 7.1% | 3.2% |
| Structure & body | 2.3% | 1.4% |
| Fuel & exhaust | 1.2% | 1.3% |
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 | SYM AD12W Jet 4 125 | Piaggio Vespa |
|---|---|---|
| 2018 | 75.1% | 81.5% |
| 2019 | 69.2% | 82.6% |
| 2020 | 75.3% | 85.6% |
| 2021 | 75.2% | 85.8% |
| 2022 | 72.3% | 86.6% |
| 2023 | 74.5% | 86.5% |
| 2024 | 72.5% | 87.2% |
| 2025 | 80.4% | 87.4% |
Each year mixes bikes of different ages, so a fleet that is getting older tends to slip.
Pass rate by mileage
| Mileage | SYM AD12W Jet 4 125 | Piaggio Vespa |
|---|---|---|
| 0k-10k miles | 80.1% | 85.0% |
| 10k-20k miles | 70.2% | 77.0% |
| 20k-30k miles | 69.1% | 75.3% |
| 30k-40k miles | 60.2% | 75.4% |
Bands with fewer than 30 tests for either bike are left out.
SYM AD12W Jet 4 125 vs Piaggio Vespa FAQ
Which is more reliable, the SYM AD12W Jet 4 125 or the Piaggio Vespa?
The Piaggio Vespa passes its MOT first time more often than the SYM AD12W Jet 4 125: 80.7% vs 72.9%, a 7.8-point lead. Adjusted for age, mileage and test class, the Piaggio Vespa still comes out ahead: +2.1 points vs comparable bikes for the SYM AD12W Jet 4 125, +5.9 for the Piaggio Vespa. An MOT checks roadworthiness items, not engine or gearbox internals.
What does the SYM AD12W Jet 4 125 fail its MOT on most?
Tyres & wheels: 8.1% of SYM AD12W Jet 4 125 MOT tests failed on it, then brakes (8.1%).
What does the Piaggio Vespa fail its MOT on most?
Lights & signalling: 6.4% of Piaggio Vespa MOT tests failed on it, then tyres & wheels (3.8%).
Which holds up better at high mileage, the SYM AD12W Jet 4 125 or the Piaggio Vespa?
At 30k-40k miles the Piaggio Vespa passes first time more often: 60.2% for the SYM AD12W Jet 4 125 vs 75.4% for the Piaggio Vespa.
See each bike's full report (trend, mileage curve, failure breakdown and rivals) on its own page.