Longjia LJ 50 QT-K vs Peugeot Speedfight

The Peugeot Speedfight passes its MOT first time more often than the Longjia LJ 50 QT-K: 65.2% vs 57.3%, a 7.9-point lead.

MOT reliability, side by side

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

Metric	Longjia LJ 50 QT-K	Peugeot Speedfight
First-time pass rate	57.3%	65.2%
Outright fail rate	31.8%	26.3%
Vs comparable bikes (age & mileage adjusted)	-17.0 pts	-5.3 pts
Engine size	49cc	49cc
Rank among all models	#5295 of 5428	#5008 of 5428
Median miles at test	5,822	13,547
MOT tests analysed	1,184	83,728
Most common failure	lighting and signalling	lighting and signalling

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	Longjia LJ 50 QT-K	Peugeot Speedfight
Lights & signalling	20.7%	15.4%
Steering & suspension	16.6%	12.9%
Brakes	12.9%	10.8%
Tyres & wheels	5.2%	4.7%
Fuel & exhaust	4.1%	2.5%
Structure & body	3.0%	2.3%

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	Longjia LJ 50 QT-K	Peugeot Speedfight
2012	62.7%	61.2%
2013	57.2%	61.2%
2014	48.5%	61.7%
2015	58.0%	64.4%
2016	55.4%	63.0%
2017	56.5%	68.5%
2018	74.4%	69.6%
2019	64.7%	68.9%

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	Longjia LJ 50 QT-K	Peugeot Speedfight
0k-10k miles	60.7%	73.1%
10k-20k miles	44.2%	63.3%

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

Longjia LJ 50 QT-K vs Peugeot Speedfight FAQ

answers computed from the data above · terms in the glossary

Which is more reliable, the Longjia LJ 50 QT-K or the Peugeot Speedfight?

The Peugeot Speedfight passes its MOT first time more often than the Longjia LJ 50 QT-K: 65.2% vs 57.3%, a 7.9-point lead. Adjusted for age, mileage and test class, the Peugeot Speedfight still comes out ahead: -17.0 points vs comparable bikes for the Longjia LJ 50 QT-K, -5.3 for the Peugeot Speedfight. An MOT checks roadworthiness items, not engine or gearbox internals.

What does the Longjia LJ 50 QT-K fail its MOT on most?

Lights & signalling: 20.7% of Longjia LJ 50 QT-K MOT tests failed on it, then steering & suspension (16.6%).

What does the Peugeot Speedfight fail its MOT on most?

Lights & signalling: 15.4% of Peugeot Speedfight MOT tests failed on it, then steering & suspension (12.9%).

LONGJIA LJ 50 QT-K 57.3% pass · 1,184 tests PEUGEOT SPEEDFIGHT 65.2% pass · 83.7k tests

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