BIKERELIABILITY Reg check
League table/ CPI/FORMULA
Model report · 2005–2025

CPI FORMULA

49cc Petrol Class 1
61.8%
first-time pass rate
27.2%
failed outright
3,144
median miles at test
136
MOT tests, 2005–2025
-15.2pp
vs expected · age & mileage

The pass rate is the MOT first-time pass: a roadworthiness check of the items an MOT covers (brakes, lights, tyres, steering, structure, emissions), not a full mechanical inspection of engine or gearbox internals. It is a reliability signal, not a complete measure of mechanical reliability. What this measures.

“vs expected” adjusts for age, mileage and test class, so a cherished classic and a hard-used commuter are compared fairly. How this works.

What fails on a FORMULA

failure defects by component group · advisories excluded
Component group Share of defects Defects % of defects
lamps and reflectors
28 25.7
brakes
17 15.6
lighting and signalling
17 15.6
steering and suspension
14 12.8
tyres and wheels
9 8.3
tyres
8 7.3
structure and attachments
5 4.6
audible warning (Horn)
4 3.7
steering
4 3.7
suspension
3 2.8

Defects recorded against failed normal tests, 2005–2025, grouped by DVSA inspection section. One test can record multiple defects.

How rivals compare

same type, similar capacity, high test volume

On first-time pass rate the FORMULA beats 0 of its 4 closest rivals (PEUGEOT SPEEDFIGHT, PIAGGIO ZIP, PIAGGIO NRG).

Rivals share this bike's type and sit within ±30% of its engine capacity, ≥ 5,000 tests. Card colour = better/worse first-time pass rate than the FORMULA.

Compare with any bike

rival not listed above? pick any model to see it head-to-head with the Formula

Pass rate by registration year

how each model-year cohort fares · registration year from first use date

Best year to buy used: 2014 (70.3% pass). Weakest: 2014 (70.3%).

First-time pass rate by the year each bike was first registered (cohorts with ≥ 50 tests). Older cohorts are survivors: the worst examples have already left the road, which tends to lift the earliest years.

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