Ajs DD 250 S-9B vs Yamaha YP250

The Yamaha YP250 passes its MOT first time more often than the Ajs DD 250 S-9B: 82.5% vs 74.9%, a 7.6-point lead.

MOT reliability, side by side

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

Metric	Ajs DD 250 S-9B	Yamaha YP250
First-time pass rate	74.9%	82.5%
Outright fail rate	14.4%	12.3%
Vs comparable bikes (age & mileage adjusted)	-13.0 pts	-2.3 pts
Engine size	234cc	249cc
Rank among all models	#4314 of 5428	#3073 of 5428
Median miles at test	4,592	15,613
MOT tests analysed	215	12,433
Most common failure	lighting and signalling	brakes

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.

Pass rate by mileage

first-time MOT pass rate by miles on the clock at test

Mileage	Ajs DD 250 S-9B	Yamaha YP250
0k-10k miles	77.1%	88.6%
10k-20k miles	63.3%	82.5%

Bands with fewer than 30 tests for either bike are left out.

AJS DD 250 S-9B 74.9% pass · 215 tests YAMAHA YP250 82.5% pass · 12.4k tests

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