Ajs ZN vs Yamaha YBR 125

The Ajs ZN passes its MOT first time more often than the Yamaha YBR 125: 72.4% vs 71.0%, a 1.4-point lead.

MOT reliability, side by side

first-time pass rate, outright fail rate and tests analysed · 2005–2025

Metric	Ajs ZN	Yamaha YBR 125
First-time pass rate	72.4%	71.0%
Outright fail rate	20.3%	17.1%
Vs comparable bikes (age & mileage adjusted)	-6.7 pts	-1.1 pts
Engine size	125cc	124cc
Rank among all models	#4548 of 5428	#4664 of 5428
Median miles at test	4,898	10,652
MOT tests analysed	286	124,897
Most common failure	lamps and reflectors	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.

Pass rate by test year

first-time MOT pass rate in each calendar year both bikes were tested

Test year	Ajs ZN	Yamaha YBR 125
2019	54.3%	71.8%
2020	75.3%	73.4%
2021	71.7%	71.6%
2022	72.1%	71.3%
2023	76.7%	71.1%

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	Ajs ZN	Yamaha YBR 125
0k-10k miles	72.4%	76.8%
10k-20k miles	56.8%	67.4%

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

AJS ZN 72.4% pass · 286 tests YAMAHA YBR 125 71.0% pass · 125k tests

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