TGB 304 vs Yamaha YBR 125

The Yamaha YBR 125 passes its MOT first time more often than the TGB 304: 71.0% vs 70.2%, a 0.8-point lead.

MOT reliability, side by side

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

Metric	TGB 304	Yamaha YBR 125
First-time pass rate	70.2%	71.0%
Outright fail rate	20.0%	17.1%
Vs comparable bikes (age & mileage adjusted)	-0.2 pts	-1.1 pts
Engine size	124cc	124cc
Rank among all models	#4717 of 5428	#4664 of 5428
Median miles at test	11,781	10,652
MOT tests analysed	1,243	124,897
Most common failure	steering and suspension	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	TGB 304	Yamaha YBR 125
Lights & signalling	7.7%	8.5%
Steering & suspension	8.7%	6.5%
Brakes	7.6%	5.9%
Tyres & wheels	5.6%	4.4%
Structure & body	1.4%	3.8%
Drive system	0%	2.9%
Fuel & exhaust	2.1%	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	TGB 304	Yamaha YBR 125
2010	73.6%	71.4%
2011	75.2%	69.1%
2012	74.2%	69.1%
2013	68.6%	69.5%
2014	63.4%	70.0%
2015	70.0%	71.2%
2016	67.7%	71.3%
2017	68.9%	70.7%

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	TGB 304	Yamaha YBR 125
0k-10k miles	75.0%	76.8%
10k-20k miles	67.7%	67.4%
20k-30k miles	65.7%	63.8%

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

TGB 304 vs Yamaha YBR 125 FAQ

answers computed from the data above · terms in the glossary

Which is more reliable, the TGB 304 or the Yamaha YBR 125?

The Yamaha YBR 125 passes its MOT first time more often than the TGB 304: 71.0% vs 70.2%, a 0.8-point lead. Adjusted for age, mileage and test class the two are level (-0.2 vs -1.1 points against comparable bikes), so the raw gap is mostly down to how old and how used each fleet is. An MOT checks roadworthiness items, not engine or gearbox internals.

What does the TGB 304 fail its MOT on most?

Steering & suspension: 8.7% of TGB 304 MOT tests failed on it, then lights & signalling (7.7%).

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 TGB 304 or the Yamaha YBR 125?

At 20k-30k miles the TGB 304 passes first time more often: 65.7% for the TGB 304 vs 63.8% for the Yamaha YBR 125.

TGB 304 70.2% pass · 1,243 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.