BIKERELIABILITY
MOT DATA · GREAT BRITAIN · 2005–2025
League table/ AJS/MODEL 31
Model report · 2005–2025

AJS MODEL 31

650cc Petrol Class 2
#587 of 5426 overall #9 of 45 AJSs #357 of 2787 other bikes
91.4%
first-time pass rate
1.6%
failed outright
23,465
median miles at test
314
MOT tests, 2005–2025

Pass rate over time

first-time pass rate by test year · 2006–2010

The MODEL 31's first-time pass rate has fallen 2.8 points since 2006, 90.3% to 87.5%.

81%89%96%2006: 90.3% pass (31 tests)2007: 83.9% pass (31 tests)2008: 90.0% pass (30 tests)2009: 93.9% pass (33 tests)2010: 87.5% pass (32 tests)20062010

Pass rate by mileage

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

A low-mileage MODEL 31 passes first time 90.8% of the time; by 40k that's 92.6%.

90%92%94%0k: 90.8% pass (87 tests)10k: 92.7% pass (55 tests)20k: 92.1% pass (38 tests)30k: 92.3% pass (39 tests)40k: 92.6% pass (54 tests)0k20k40k

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 MODEL 31

failure defects by component group · advisories excluded
Component group Share of defects Defects % of defects
steering and suspension
3 37.5
tyres and wheels
2 25
brakes
1 12.5
driving controls
1 12.5
lighting and signalling
1 12.5

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

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 MODEL 31.

Pass rate by registration year

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

Best year to buy used: 1959 (93.0% pass). Weakest: 1961 (90.0%).

89%92%94%1959: 93.0% pass (57 tests)1960: 91.9% pass (74 tests)1961: 90.0% pass (50 tests)195919601961

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.