Chinese 125cc overall
26.0%
MOT fail rate
Japanese ≤500cc overall
21.0%
MOT fail rate
Gap at year 12
2.2pp
Down from 10.7pp at year 1
Chinese 125cc
Japanese ≤500cc

The flat line tells the real story. Chinese bikes fail at ~25% from year one and barely move. Japanese bikes start at 14.3% and climb steadily — ageing into Chinese territory by year twelve. The reliability gap is a manufacturing problem, not a longevity one.