Data as of: DVSA MOT results to 2025
Bsa B44 vs Kawasaki ER5
The Bsa B44 passes its MOT first time more often than the Kawasaki ER5: 90.2% vs 77.4%, a 12.8-point lead.
MOT reliability, side by side
| Metric | Bsa B44 | Kawasaki ER5 |
|---|---|---|
| First-time pass rate | 90.2% | 77.4% |
| Outright fail rate | 3.9% | 14.2% |
| Vs comparable bikes (age & mileage adjusted) | +0.4 pts | -6.2 pts |
| Engine size | 441cc | 498cc |
| Rank among all models | #884 of 5428 | #3999 of 5428 |
| Median miles at test | 8,685 | 21,259 |
| MOT tests analysed | 620 | 53,115 |
| Most common failure | steering and suspension | 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 | Bsa B44 | Kawasaki ER5 |
|---|---|---|
| Steering & suspension | 1.8% | 5.4% |
| Lights & signalling | 1.9% | 5.1% |
| Brakes | 0.5% | 6.0% |
| Tyres & wheels | 1.0% | 3.6% |
| Drive system | 0.5% | 2.3% |
| Structure & body | 0.5% | 1.3% |
| Fuel & exhaust | 0.2% | 0.8% |
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 | Bsa B44 | Kawasaki ER5 |
|---|---|---|
| 2010 | 93.5% | 76.2% |
| 2011 | 95.0% | 77.0% |
| 2012 | 90.5% | 76.1% |
| 2013 | 92.2% | 73.4% |
| 2014 | 88.1% | 73.9% |
| 2015 | 89.8% | 76.4% |
| 2016 | 95.7% | 75.6% |
| 2017 | 94.2% | 75.7% |
Each year mixes bikes of different ages, so a fleet that is getting older tends to slip.
Pass rate by mileage
| Mileage | Bsa B44 | Kawasaki ER5 |
|---|---|---|
| 0k-10k miles | 89.8% | 87.5% |
| 10k-20k miles | 93.1% | 79.5% |
| 20k-30k miles | 91.4% | 75.4% |
Bands with fewer than 30 tests for either bike are left out.
Bsa B44 vs Kawasaki ER5 FAQ
Which is more reliable, the Bsa B44 or the Kawasaki ER5?
The Bsa B44 passes its MOT first time more often than the Kawasaki ER5: 90.2% vs 77.4%, a 12.8-point lead. Adjusted for age, mileage and test class, the Bsa B44 still comes out ahead: +0.4 points vs comparable bikes for the Bsa B44, -6.2 for the Kawasaki ER5. An MOT checks roadworthiness items, not engine or gearbox internals.
What does the Bsa B44 fail its MOT on most?
Lights & signalling: 1.9% of Bsa B44 MOT tests failed on it, then steering & suspension (1.8%).
What does the Kawasaki ER5 fail its MOT on most?
Brakes: 6.0% of Kawasaki ER5 MOT tests failed on it, then steering & suspension (5.4%).
Which holds up better at high mileage, the Bsa B44 or the Kawasaki ER5?
At 20k-30k miles the Bsa B44 passes first time more often: 91.4% for the Bsa B44 vs 75.4% for the Kawasaki ER5.
See each bike's full report (trend, mileage curve, failure breakdown and rivals) on its own page.