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

Data as of: DVSA MOT results to 2025

Royal Enfield Bullet vs Suzuki AN400

The Royal Enfield Bullet passes its MOT first time more often than the Suzuki AN400: 87.9% vs 86.2%, a 1.7-point lead.

MOT reliability, side by side

first-time pass rate, outright fail rate and tests analysed · 2005–2025
Metric Royal Enfield Bullet Suzuki AN400
First-time pass rate 87.9% 86.2%
Outright fail rate 5.2% 9.8%
Vs comparable bikes (age & mileage adjusted) +0.7 pts +1.3 pts
Engine size 406cc 385cc
Rank among all models #1639 of 5428 #2148 of 5428
Median miles at test 7,247 15,861
MOT tests analysed 5,229 27,056
Most common failure lighting and signalling 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

share of each bike's MOT tests that failed on the component · lower is better
Component Royal Enfield Bullet Suzuki AN400
Brakes 1.5% 4.4%
Lights & signalling 3.3% 2.6%
Tyres & wheels 0.7% 3.2%
Steering & suspension 1.4% 2.3%
Fuel & exhaust 0.5% 0.4%
Structure & body 0.5% 0.3%
Drive system 0.2% 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

first-time MOT pass rate in each calendar year both bikes were tested
Test year Royal Enfield Bullet Suzuki AN400
2018 87.5% 85.7%
2019 83.0% 84.4%
2020 92.1% 84.5%
2021 93.9% 85.1%
2022 90.6% 83.0%
2023 84.4% 83.0%
2024 89.3% 83.1%
2025 86.8% 86.9%

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 Suzuki AN400
0k-10k miles 87.8% 91.7%
10k-20k miles 87.8% 86.7%
20k-30k miles 88.1% 82.7%
30k-40k miles 85.3% 81.0%
40k-50k miles 90.1% 79.7%
50k-60k miles 89.2% 75.7%

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

Royal Enfield Bullet vs Suzuki AN400 FAQ

answers computed from the data above · terms in the glossary

Which is more reliable, the Royal Enfield Bullet or the Suzuki AN400?

The Royal Enfield Bullet passes its MOT first time more often than the Suzuki AN400: 87.9% vs 86.2%, a 1.7-point lead. Adjusted for age, mileage and test class the two are level (+0.7 vs +1.3 points against comparable bikes), so the raw gap is mostly down to how old and how used each fleet is. An MOT checks roadworthiness items, not engine or gearbox internals.

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

Lights & signalling: 3.3% of Royal Enfield Bullet MOT tests failed on it, then brakes (1.5%).

What does the Suzuki AN400 fail its MOT on most?

Brakes: 4.4% of Suzuki AN400 MOT tests failed on it, then tyres & wheels (3.2%).

Which holds up better at high mileage, the Royal Enfield Bullet or the Suzuki AN400?

At 50k-60k miles the Royal Enfield Bullet passes first time more often: 89.2% for the Royal Enfield Bullet vs 75.7% for the Suzuki AN400.

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