TRIUMPH TWENTY ONE

350cc Petrol Class 2

#414 of 5426 overall #27 of 175 TRIUMPHs #256 of 2787 other bikes

92.3%

first-time pass rate

4.3%

failed outright

16,340

median miles at test

884

MOT tests, 2005–2025

Pass rate over time

first-time pass rate by test year · 2006–2017

The TWENTY ONE's first-time pass rate has risen 3.5 points since 2006, 94.4% to 97.9%.

Pass rate by mileage

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

A low-mileage TWENTY ONE passes first time 93.8% of the time; by 50k that's 86.2%.

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 TWENTY ONE

failure defects by component group · advisories excluded

Component group	Defects	% of defects	vs all bikes
lighting and signalling	23	27.1	0.5×
brakes	19	22.4	0.3×
steering and suspension	16	18.8	0.5×
tyres and wheels	11	12.9	0.4×
fuel and exhaust	4	4.7	0.3×
driving controls	4	4.7	1.9×
steering	3	3.5	0.5×
lamps and reflectors	2	2.4	0.1×
structure and attachments	2	2.4	0.3×
reg plates and vin	1	1.2	0.2×

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 TWENTY ONE 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 TWENTY ONE.

Pass rate by registration year

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

Best year to buy used: 1965 (97.8% pass). Weakest: 1964 (87.4%).

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.

TRIUMPH TWENTY ONE FAQ

answers computed from the data above · terms in the glossary

Is the TRIUMPH TWENTY ONE reliable?

The TRIUMPH TWENTY ONE is more reliable than average for its class: 92.3% of its 884 MOT tests (2005–2025) passed first time, against a class average of 84.9%. That ranks it #414 of 5426 models.

What does a TWENTY ONE fail its MOT on most?

lighting and signalling — 27% of all defects recorded against failed TWENTY ONE tests.

What is the best year of TWENTY ONE to buy used?

By first-time pass rate, 1965-registered examples do best (97.8%) and 1964 worst (87.4%). Condition and history still trump the year.

How many miles will a TWENTY ONE last?

The median TWENTY ONE shows 16,340 miles at test, and examples around 50k miles still pass 86.2% of the time — mileage alone rarely kills one.