Data as of: DVSA MOT results to 2025
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.
Pass rate over time
The CS50's first-time pass rate has risen 5.9 points since 2005, 53.7% to 59.6%.
Pass rate by mileage
A low-mileage CS50 passes first time 69.3% of the time; by 20k that's 53.7%.
First-time pass rate by odometer reading at test, 10,000-mile bands for this model. Mileage is the strongest reliability signal. See the full curve.
What fails on a CS50
| Component group | Share of defects | Defects | % of defects | vs all bikes |
|---|---|---|---|---|
| lighting and signalling |
|
1,263 | 38.2 | 3.5× |
| brakes |
|
714 | 21.6 | 2.4× |
| steering and suspension |
|
371 | 11.2 | 1.9× |
| tyres and wheels |
|
275 | 8.3 | 2.1× |
| lamps and reflectors |
|
261 | 7.9 | 1.5× |
| fuel and exhaust |
|
212 | 6.4 | 4.9× |
| body and structure |
|
86 | 2.6 | 2.9× |
| structure and attachments |
|
47 | 1.4 | 1.0× |
| steering |
|
44 | 1.3 | 1.7× |
| tyres |
|
37 | 1.1 | 0.9× |
Defects recorded against failed normal tests, 2005–2025, grouped by DVSA inspection section. One test can record multiple defects. "vs all bikes" is how often this model's tests record a defect in the group, as a multiple of the all-bike rate.
How rivals compare
On first-time pass rate the CS50 beats 2 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 CS50.
Compare with any bike
More YAMAHA models
Pass rate by registration year
Highest pass rate: 2011 (75.4%). Lowest: 2012 (61.9%). Every CS50 year compared →
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.
YAMAHA CS50 FAQ
Is the YAMAHA CS50 reliable?
The YAMAHA CS50 is less reliable than average for its class: 67.4% of its 5,046 MOT tests (2005–2025) passed first time, against a class average of 73.4%. That ranks it #4889 of 5428 models.
What does a CS50 fail its MOT on most?
lighting and signalling: 38% of all defects recorded against failed CS50 tests.
What is the best year of CS50 to buy used?
By first-time pass rate, 2011-registered examples do best (75.4%) and 2012 worst (61.9%). Condition and history still trump the year.
How many miles will a CS50 last?
The median CS50 shows 4,453 miles at test, and examples around 20k miles still pass 53.7% of the time, so mileage alone rarely decides the result.
Embed this bike
Free to embed on your site, blog or forum: a live Yamaha CS50 reliability card that stays up to date and links back here. More on the free API page.