Data as of: DVSA MOT results to 2025
MZ Mastiff vs Kawasaki ZX-6R
The MZ Mastiff passes its MOT first time more often than the Kawasaki ZX-6R: 81.3% vs 78.1%, a 3.2-point lead.
MOT reliability, side by side
| Metric | MZ Mastiff | Kawasaki ZX-6R |
|---|---|---|
| First-time pass rate | 81.3% | 78.1% |
| Outright fail rate | 11.1% | 14.0% |
| Vs comparable bikes (age & mileage adjusted) | -4.4 pts | -5.8 pts |
| Engine size | 660cc | 599cc |
| Rank among all models | #3318 of 5428 | #3895 of 5428 |
| Median miles at test | 12,562 | 19,446 |
| MOT tests analysed | 888 | 173,956 |
| 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 | MZ Mastiff | Kawasaki ZX-6R |
|---|---|---|
| Lights & signalling | 6.0% | 6.1% |
| Brakes | 2.9% | 5.2% |
| Steering & suspension | 2.3% | 4.6% |
| Tyres & wheels | 2.5% | 3.6% |
| Structure & body | 1.2% | 1.2% |
| Fuel & exhaust | 1.0% | 0.8% |
| Drive system | 0.7% | 1.0% |
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 | MZ Mastiff | Kawasaki ZX-6R |
|---|---|---|
| 2013 | 69.5% | 75.5% |
| 2014 | 73.5% | 76.4% |
| 2015 | 82.2% | 76.7% |
| 2016 | 76.2% | 77.7% |
| 2017 | 83.7% | 77.1% |
| 2019 | 90.0% | 78.5% |
| 2021 | 90.9% | 78.6% |
| 2022 | 100.0% | 79.4% |
Each year mixes bikes of different ages, so a fleet that is getting older tends to slip.
Pass rate by mileage
| Mileage | MZ Mastiff | Kawasaki ZX-6R |
|---|---|---|
| 0k-10k miles | 80.5% | 86.1% |
| 10k-20k miles | 82.4% | 80.6% |
| 20k-30k miles | 78.2% | 75.4% |
| 30k-40k miles | 84.2% | 71.8% |
Bands with fewer than 30 tests for either bike are left out.
MZ Mastiff vs Kawasaki ZX-6R FAQ
Which is more reliable, the MZ Mastiff or the Kawasaki ZX-6R?
The MZ Mastiff passes its MOT first time more often than the Kawasaki ZX-6R: 81.3% vs 78.1%, a 3.2-point lead. Adjusted for age, mileage and test class, the MZ Mastiff still comes out ahead: -4.4 points vs comparable bikes for the MZ Mastiff, -5.8 for the Kawasaki ZX-6R. An MOT checks roadworthiness items, not engine or gearbox internals.
What does the MZ Mastiff fail its MOT on most?
Lights & signalling: 6.0% of MZ Mastiff MOT tests failed on it, then brakes (2.9%).
What does the Kawasaki ZX-6R fail its MOT on most?
Lights & signalling: 6.1% of Kawasaki ZX-6R MOT tests failed on it, then brakes (5.2%).
Which holds up better at high mileage, the MZ Mastiff or the Kawasaki ZX-6R?
At 30k-40k miles the MZ Mastiff passes first time more often: 84.2% for the MZ Mastiff vs 71.8% for the Kawasaki ZX-6R.
See each bike's full report (trend, mileage curve, failure breakdown and rivals) on its own page.