BIKERELIABILITY Reg check
Head-to-head · 2005–2025

Data as of: DVSA MOT results to 2025

Royal Enfield Bullet 350 vs Kawasaki ZXR400

The Royal Enfield Bullet 350 passes its MOT first time more often than the Kawasaki ZXR400: 89.6% vs 73.1%, a 16.5-point lead.

MOT reliability, side by side

first-time pass rate, outright fail rate and tests analysed · 2005–2025
Metric Royal Enfield Bullet 350 Kawasaki ZXR400
First-time pass rate 89.6% 73.1%
Outright fail rate 5.3% 18.9%
Vs comparable bikes (age & mileage adjusted) +2.7 pts -9.9 pts
Engine size 346cc 398cc
Rank among all models #1077 of 5428 #4490 of 5428
Median miles at test 6,094 23,651
MOT tests analysed 7,044 14,200
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

share of each bike's MOT tests that failed on the component · lower is better
Component Royal Enfield Bullet 350 Kawasaki ZXR400
Lights & signalling 3.1% 9.1%
Brakes 1.1% 7.9%
Steering & suspension 0.9% 7.9%
Tyres & wheels 0.6% 4.0%
Fuel & exhaust 0.4% 2.4%
Structure & body 0.4% 2.2%
Drive system 0.2% 1.9%

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

first-time MOT pass rate in each calendar year both bikes were tested
Test year Royal Enfield Bullet 350 Kawasaki ZXR400
2018 93.5% 75.9%
2019 89.9% 79.3%
2020 89.8% 80.4%
2021 88.5% 81.2%
2022 89.2% 86.3%
2023 91.3% 82.8%
2024 92.1% 80.0%
2025 86.1% 88.4%

Each year mixes bikes of different ages, so a fleet that is getting older tends to slip.

Pass rate by mileage

first-time MOT pass rate by miles on the clock at test
Mileage Royal Enfield Bullet 350 Kawasaki ZXR400
0k-10k miles 90.2% 87.1%
10k-20k miles 88.8% 77.4%
20k-30k miles 87.7% 69.9%
30k-40k miles 88.1% 67.8%
40k-50k miles 85.5% 64.7%

Bands with fewer than 30 tests for either bike are left out.

Royal Enfield Bullet 350 vs Kawasaki ZXR400 FAQ

answers computed from the data above · terms in the glossary

Which is more reliable, the Royal Enfield Bullet 350 or the Kawasaki ZXR400?

The Royal Enfield Bullet 350 passes its MOT first time more often than the Kawasaki ZXR400: 89.6% vs 73.1%, a 16.5-point lead. Adjusted for age, mileage and test class, the Royal Enfield Bullet 350 still comes out ahead: +2.7 points vs comparable bikes for the Royal Enfield Bullet 350, -9.9 for the Kawasaki ZXR400. An MOT checks roadworthiness items, not engine or gearbox internals.

What does the Royal Enfield Bullet 350 fail its MOT on most?

Lights & signalling: 3.1% of Royal Enfield Bullet 350 MOT tests failed on it, then brakes (1.1%).

What does the Kawasaki ZXR400 fail its MOT on most?

Lights & signalling: 9.1% of Kawasaki ZXR400 MOT tests failed on it, then brakes (7.9%).

Which holds up better at high mileage, the Royal Enfield Bullet 350 or the Kawasaki ZXR400?

At 40k-50k miles the Royal Enfield Bullet 350 passes first time more often: 85.5% for the Royal Enfield Bullet 350 vs 64.7% for the Kawasaki ZXR400.

See each bike's full report (trend, mileage curve, failure breakdown and rivals) on its own page.