Yamaha Yn50 common MOT failures and failure rate
What a Yamaha Yn50 fails its MOT on, from real DVSA test data, and the part that resolves each item.
Based on 23,189 MOT tests in DVSA data.
About 23.6% of MOT tests recorded on the Yamaha Yn50 in DVSA data end in a failure. The same handful of items account for most of them.
Its most common failure is brakes, which makes up 37.2% of the Yamaha Yn50's failures, followed by brakes, lamps & electrical, tyres, steering. Each item below links to the part that resolves it. Confirm the exact fitment against your registration or VIN before buying, and have safety-critical work done by a competent mechanic.
What it fails on, and why
Brake failures cover worn pads and discs, an imbalance between wheels, corroded or scored discs, or a binding caliper. Braking efficiency is measured on a rolling road, so a spongy or pulling brake shows up as a low reading.
Lighting is the single most common MOT failure and the cheapest to put right. A blown headlight, brake-light or number-plate bulb, a cracked lens, or a headlamp beam that points too high or low will all fail. Most are a two-minute bulb swap.
Tyres fail for tread below the 1.6mm legal limit across the central three-quarters, uneven or exposed-cord wear, or sidewall damage. The tester inspects all four; a single illegal tyre is a fail.
Steering faults are typically worn track-rod ends or ball joints, play in the rack, or a split gaiter letting grease out and dirt in. Excessive free play at the wheel fails.
This covers a range of smaller items, from a non-working horn to a warning light left on.
Exhaust failures cover leaks, insecure mountings and emissions over the limit. A blowing exhaust, a failed lambda reading or a diesel that smokes beyond the limit will fail.
Failure rate by year
How the MOT failure rate varies by the car's year of first registration (older examples generally fail more as wear sets in).
The parts that fix each
If your car has just failed, you have 10 working days to fix the items and get a free partial retest. These are the usual parts; confirm the exact fitment against your registration or VIN before buying.
Other models
Sources: DVSA MOT History API: MOT test results and defect data · DVSA MOT testing data for Great Britain