BIKERELIABILITY Reg check
League table/ SYM Jet 4 125 E4/vs Yamaha Nmax 125
Head-to-head · 2005–2025

Data as of: DVSA MOT results to 2025

SYM Jet 4 125 E4 vs Yamaha Nmax 125

The Yamaha Nmax 125 passes its MOT first time more often than the SYM Jet 4 125 E4: 82.2% vs 72.0%, a 10.2-point lead.

MOT reliability, side by side

first-time pass rate, outright fail rate and tests analysed · 2005–2025
Metric SYM Jet 4 125 E4 Yamaha Nmax 125
First-time pass rate 72.0% 82.2%
Outright fail rate 19.5% 11.4%
Vs comparable bikes (age & mileage adjusted) -1.7 pts +9.5 pts
Engine size 125cc 125cc
Rank among all models #4581 of 5428 #3145 of 5428
Median miles at test 9,305 30,236
MOT tests analysed 1,207 33,779
Most common failure brakes 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 SYM Jet 4 125 E4 Yamaha Nmax 125
Brakes 10.7% 5.3%
Lights & signalling 9.6% 4.2%
Steering & suspension 4.1% 5.0%
Tyres & wheels 5.1% 3.7%
Structure & body 2.5% 0.6%

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 SYM Jet 4 125 E4 Yamaha Nmax 125
2020 79.1% 88.4%
2021 71.1% 84.9%
2022 66.9% 83.5%
2023 70.7% 81.5%
2024 73.7% 79.8%
2025 74.5% 80.8%

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 SYM Jet 4 125 E4 Yamaha Nmax 125
0k-10k miles 76.0% 90.9%
10k-20k miles 68.1% 84.2%
20k-30k miles 58.9% 81.9%
30k-40k miles 56.3% 79.2%

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

SYM Jet 4 125 E4 vs Yamaha Nmax 125 FAQ

answers computed from the data above · terms in the glossary

Which is more reliable, the SYM Jet 4 125 E4 or the Yamaha Nmax 125?

The Yamaha Nmax 125 passes its MOT first time more often than the SYM Jet 4 125 E4: 82.2% vs 72.0%, a 10.2-point lead. Adjusted for age, mileage and test class, the Yamaha Nmax 125 still comes out ahead: -1.7 points vs comparable bikes for the SYM Jet 4 125 E4, +9.5 for the Yamaha Nmax 125. An MOT checks roadworthiness items, not engine or gearbox internals.

What does the SYM Jet 4 125 E4 fail its MOT on most?

Brakes: 10.7% of SYM Jet 4 125 E4 MOT tests failed on it, then lights & signalling (9.6%).

What does the Yamaha Nmax 125 fail its MOT on most?

Brakes: 5.3% of Yamaha Nmax 125 MOT tests failed on it, then steering & suspension (5.0%).

Which holds up better at high mileage, the SYM Jet 4 125 E4 or the Yamaha Nmax 125?

At 30k-40k miles the Yamaha Nmax 125 passes first time more often: 56.3% for the SYM Jet 4 125 E4 vs 79.2% for the Yamaha Nmax 125.

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