Generic Sirion vs Piaggio NRG

The Generic Sirion passes its MOT first time more often than the Piaggio NRG: 72.3% vs 65.5%, a 6.8-point lead.

MOT reliability, side by side

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

Metric	Generic Sirion	Piaggio NRG
First-time pass rate	72.3%	65.5%
Outright fail rate	21.7%	27.4%
Vs comparable bikes (age & mileage adjusted)	-2.8 pts	-6.0 pts
Engine size	49cc	49cc
Median miles at test	5,574	9,874
MOT tests analysed	184	40,458
Most common failure	brakes	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.

GENERIC SIRION 72.3% pass · 184 tests PIAGGIO NRG 65.5% pass · 40.5k tests

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