White Knuckle 125 vs Yamaha YBR 125

The Yamaha YBR 125 passes its MOT first time more often than the White Knuckle 125: 71.0% vs 51.7%, a 19.3-point lead.

MOT reliability, side by side

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

Metric	White Knuckle 125	Yamaha YBR 125
First-time pass rate	51.7%	71.0%
Outright fail rate	36.9%	17.1%
Vs comparable bikes (age & mileage adjusted)	-24.0 pts	-1.1 pts
Engine size	124cc	124cc
Rank among all models	#5384 of 5428	#4664 of 5428
Median miles at test	5,677	10,652
MOT tests analysed	924	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	White Knuckle 125	Yamaha YBR 125
Lights & signalling	25.2%	8.5%
Steering & suspension	19.8%	6.5%
Brakes	14.5%	5.9%
Structure & body	15.6%	3.8%
Tyres & wheels	5.2%	4.4%
Drive system	2.3%	2.9%
Fuel & exhaust	0.4%	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	White Knuckle 125	Yamaha YBR 125
2018	53.6%	72.0%
2019	48.6%	71.8%
2020	59.4%	73.4%
2021	51.0%	71.6%
2022	40.7%	71.3%
2023	50.7%	71.1%
2024	44.2%	70.9%
2025	57.9%	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	White Knuckle 125	Yamaha YBR 125
0k-10k miles	53.6%	76.8%
10k-20k miles	43.5%	67.4%

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

White Knuckle 125 vs Yamaha YBR 125 FAQ

answers computed from the data above · terms in the glossary

Which is more reliable, the White Knuckle 125 or the Yamaha YBR 125?

The Yamaha YBR 125 passes its MOT first time more often than the White Knuckle 125: 71.0% vs 51.7%, a 19.3-point lead. Adjusted for age, mileage and test class, the Yamaha YBR 125 still comes out ahead: -24.0 points vs comparable bikes for the White Knuckle 125, -1.1 for the Yamaha YBR 125. An MOT checks roadworthiness items, not engine or gearbox internals.

What does the White Knuckle 125 fail its MOT on most?

Lights & signalling: 25.2% of White Knuckle 125 MOT tests failed on it, then steering & suspension (19.8%).

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%).

WHITE KNUCKLE 125 51.7% pass · 924 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.