TRIUMPH 21

350cc Petrol Class 2

#197 of 5426 overall #11 of 175 TRIUMPHs #118 of 2787 other bikes

93.8%

first-time pass rate

2.2%

failed outright

19,231

median miles at test

451

MOT tests, 2005–2025

Pass rate over time

first-time pass rate by test year · 2006–2014

The 21's first-time pass rate has fallen 13.8 points since 2006, 97.1% to 83.3%.

Pass rate by mileage

how the 21's first-time pass rate falls with the odometer · class average 84.9%

A low-mileage 21 passes first time 90.6% of the time; by 50k that's 97.2%.

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 21

failure defects by component group · advisories excluded

Component group	Defects	% of defects
lighting and signalling	8	32
steering and suspension	8	32
fuel and exhaust	3	12
body and structure	2	8
tyres and wheels	2	8
drive system	1	4
brakes	1	4

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 21 beats 4 of its 4 closest rivals (SUZUKI AN400, SUZUKI DR-Z400S, YAMAHA RD350).

SUZUKI AN400 86.2% pass · 27.1k tests SUZUKI DR-Z400S 80.4% pass · 26.8k tests YAMAHA RD350 86.3% pass · 19.6k tests KAWASAKI ZXR400 73.1% pass · 14.2k 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 21.

Pass rate by registration year

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

Best year to buy used: 1958 (94.1% pass). Weakest: 1962 (89.0%).

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.