Zontes Mantis vs Yamaha YBR 125

The Yamaha YBR 125 passes its MOT first time more often than the Zontes Mantis: 71.0% vs 65.8%, a 5.2-point lead.

MOT reliability, side by side

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

Metric	Zontes Mantis	Yamaha YBR 125
First-time pass rate	65.8%	71.0%
Outright fail rate	25.7%	17.1%
Vs comparable bikes (age & mileage adjusted)	-8.3 pts	-1.1 pts
Engine size	125cc	124cc
Rank among all models	#4979 of 5428	#4664 of 5428
Median miles at test	7,745	10,652
MOT tests analysed	538	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.

What fails, side by side

share of each bike's MOT tests that failed on the component · lower is better

Component	Zontes Mantis	Yamaha YBR 125
Lights & signalling	15.8%	8.5%
Steering & suspension	9.9%	6.5%
Brakes	10.2%	5.9%
Structure & body	11.5%	3.8%
Tyres & wheels	3.2%	4.4%
Drive system	0%	2.9%
Fuel & exhaust	0%	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	Zontes Mantis	Yamaha YBR 125
2019	72.7%	71.8%
2020	76.0%	73.4%
2021	67.2%	71.6%
2022	57.1%	71.3%
2023	59.8%	71.1%
2024	74.4%	70.9%
2025	62.5%	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	Zontes Mantis	Yamaha YBR 125
0k-10k miles	72.5%	76.8%
10k-20k miles	56.0%	67.4%
20k-30k miles	48.8%	63.8%

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

Zontes Mantis vs Yamaha YBR 125 FAQ

answers computed from the data above · terms in the glossary

Which is more reliable, the Zontes Mantis or the Yamaha YBR 125?

The Yamaha YBR 125 passes its MOT first time more often than the Zontes Mantis: 71.0% vs 65.8%, a 5.2-point lead. Adjusted for age, mileage and test class, the Yamaha YBR 125 still comes out ahead: -8.3 points vs comparable bikes for the Zontes Mantis, -1.1 for the Yamaha YBR 125. An MOT checks roadworthiness items, not engine or gearbox internals.

What does the Zontes Mantis fail its MOT on most?

Lights & signalling: 15.8% of Zontes Mantis MOT tests failed on it, then structure & body (11.5%).

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

Lights & signalling: 8.5% of Yamaha YBR 125 MOT tests failed on it, then steering & suspension (6.5%).

Which holds up better at high mileage, the Zontes Mantis or the Yamaha YBR 125?

At 20k-30k miles the Yamaha YBR 125 passes first time more often: 48.8% for the Zontes Mantis vs 63.8% for the Yamaha YBR 125.

ZONTES MANTIS 65.8% pass · 538 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.