AJS JS

124cc Petrol Class 1

#4638 of 5426 overall #25 of 45 AJSs #331 of 734 commuter bikes

71.2%

first-time pass rate

20.2%

failed outright

9,562

median miles at test

674

MOT tests, 2005–2025

Pass rate over time

first-time pass rate by test year · 2017–2025

The JS's first-time pass rate has risen 12.2 points since 2017, 67.3% to 79.5%.

Pass rate by mileage

how the JS's first-time pass rate falls with the odometer · class average 73.4%

A low-mileage JS passes first time 75.4% of the time; by 20k that's 60.0%.

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 JS

failure defects by component group · advisories excluded

Component group	Defects	% of defects	vs all bikes
lamps and reflectors	84	24.9	4.9×
brakes	70	20.7	1.8×
structure and attachments	53	15.7	8.9×
lighting and signalling	30	8.9	0.7×
tyres	25	7.4	5.0×
steering	23	6.8	7.8×
suspension	22	6.5	3.8×
steering and suspension	12	3.6	0.6×
tyres and wheels	10	3	0.6×
drive system	9	2.7	1.4×

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

same type, similar capacity, high test volume

On first-time pass rate the JS beats 2 of its 4 closest rivals (YAMAHA YBR 125, HONDA CG125, HONDA CBF125).

YAMAHA YBR 125 71.0% pass · 125k tests HONDA CG125 72.2% pass · 89.3k tests HONDA CBF125 73.3% pass · 84.4k tests GILERA RUNNER 70.8% pass · 69.9k 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 JS.

Pass rate by registration year

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

Best year to buy used: 2015 (75.0% pass). Weakest: 2013 (66.7%).

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.

AJS JS FAQ

answers computed from the data above · terms in the glossary

Is the AJS JS reliable?

The AJS JS is less reliable than average for its class: 71.2% of its 674 MOT tests (2005–2025) passed first time, against a class average of 73.4%. That ranks it #4638 of 5426 models.

What does a JS fail its MOT on most?

lamps and reflectors — 25% of all defects recorded against failed JS tests.

What is the best year of JS to buy used?

By first-time pass rate, 2015-registered examples do best (75.0%) and 2013 worst (66.7%). Condition and history still trump the year.

How many miles will a JS last?

The median JS shows 9,562 miles at test, and examples around 20k miles still pass 60.0% of the time — mileage alone rarely kills one.