AJS 31

650cc Petrol Class 2

#643 of 5426 overall #10 of 45 AJSs #392 of 2787 other bikes

91.2%

first-time pass rate

3.8%

failed outright

13,775

median miles at test

422

MOT tests, 2005–2025

Pass rate over time

first-time pass rate by test year · 2006–2016

The 31's first-time pass rate has risen 3.5 points since 2006, 86.8% to 90.3%.

Pass rate by mileage

how the 31's first-time pass rate falls with the odometer · class average 84.9%

A low-mileage 31 passes first time 93.2% of the time; by 50k that's 90.3%.

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 31

failure defects by component group · advisories excluded

Component group	Defects	% of defects
lighting and signalling	20	57.1
steering and suspension	7	20
brakes	5	14.3
driving controls	2	5.7
tyres and wheels	1	2.9

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 31 beats 4 of its 4 closest rivals (KAWASAKI ZX-6R, SUZUKI GSF600, YAMAHA FZS600).

KAWASAKI ZX-6R 78.1% pass · 174k tests SUZUKI GSF600 77.3% pass · 143k tests YAMAHA FZS600 82.6% pass · 137k tests HONDA VFR800 FI 86.7% pass · 89.4k tests

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 31.

Pass rate by registration year

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

Best year to buy used: 1961 (95.1% pass). Weakest: 1959 (87.7%).

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.