Zongshen ZS 125-30 vs Yamaha YBR 125

The Yamaha YBR 125 passes its MOT first time more often than the Zongshen ZS 125-30: 71.0% vs 55.6%, a 15.4-point lead.

MOT reliability, side by side

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

Metric	Zongshen ZS 125-30	Yamaha YBR 125
First-time pass rate	55.6%	71.0%
Outright fail rate	29.8%	17.1%
Vs comparable bikes (age & mileage adjusted)	-18.0 pts	-1.1 pts
Engine size	125cc	124cc
Rank among all models	#5332 of 5428	#4664 of 5428
Median miles at test	7,002	10,652
MOT tests analysed	329	124,897
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.

Pass rate by test year

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

Test year	Zongshen ZS 125-30	Yamaha YBR 125
2011	55.6%	69.1%
2012	62.2%	69.1%
2013	56.1%	69.5%
2014	68.4%	70.0%
2015	35.3%	71.2%

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	Zongshen ZS 125-30	Yamaha YBR 125
0k-10k miles	58.8%	76.8%
10k-20k miles	51.8%	67.4%

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

ZONGSHEN ZS 125-30 55.6% pass · 329 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.