Norton 99 vs Yamaha FZS600

The Norton 99 passes its MOT first time more often than the Yamaha FZS600: 93.6% vs 82.6%, a 11.0-point lead.

MOT reliability, side by side

first-time pass rate, outright fail rate and tests analysed · 2005–2025

Metric	Norton 99	Yamaha FZS600
First-time pass rate	93.6%	82.6%
Outright fail rate	1.7%	10.6%
Engine size	600cc	599cc
Rank among all models	#224 of 5428	#3052 of 5428
Median miles at test	12,718	21,612
MOT tests analysed	767	136,558
Most common failure	brakes	brakes

First-time outcomes on normal tests, 2005–2025. "Most common failure" is the component group with the most recorded defects on failed tests. Read pass rates against test counts: a smaller sample is noisier. Source: DVSA anonymised MOT results.

What fails, side by side

share of each bike's MOT tests that failed on the component · lower is better

Component	Norton 99	Yamaha FZS600
Brakes	0.7%	4.5%
Lights & signalling	0.4%	3.4%
Tyres & wheels	0.5%	2.9%
Steering & suspension	0.5%	2.7%
Drive system	0.3%	0.9%
Fuel & exhaust	0%	1.1%
Structure & body	0%	1.1%

A test that fails on two components counts once in each. Component links go to the bikes most likely to fail on it.

Pass rate by test year

first-time MOT pass rate in each calendar year both bikes were tested

Test year	Norton 99	Yamaha FZS600
2009	87.3%	81.2%
2010	92.6%	82.0%
2011	93.3%	81.1%
2012	89.7%	80.2%
2013	94.4%	81.3%
2014	91.9%	81.2%
2015	96.9%	81.1%
2016	93.8%	82.2%

Each year mixes bikes of different ages, so a fleet that is getting older tends to slip.

Pass rate by mileage

first-time MOT pass rate by miles on the clock at test

Mileage	Norton 99	Yamaha FZS600
0k-10k miles	95.5%	89.6%
10k-20k miles	92.1%	85.5%
20k-30k miles	95.1%	81.4%
30k-40k miles	90.9%	78.7%
50k-60k miles	92.2%	74.7%

Bands with fewer than 30 tests for either bike are left out.

Norton 99 vs Yamaha FZS600 FAQ

answers computed from the data above · terms in the glossary

Which is more reliable, the Norton 99 or the Yamaha FZS600?

The Norton 99 passes its MOT first time more often than the Yamaha FZS600: 93.6% vs 82.6%, a 11.0-point lead. An MOT checks roadworthiness items, not engine or gearbox internals.

What does the Norton 99 fail its MOT on most?

Brakes: 0.7% of Norton 99 MOT tests failed on it, then tyres & wheels (0.5%).

What does the Yamaha FZS600 fail its MOT on most?

Brakes: 4.5% of Yamaha FZS600 MOT tests failed on it, then lights & signalling (3.4%).

Which holds up better at high mileage, the Norton 99 or the Yamaha FZS600?

At 50k-60k miles the Norton 99 passes first time more often: 92.2% for the Norton 99 vs 74.7% for the Yamaha FZS600.

NORTON 99 93.6% pass · 767 tests YAMAHA FZS600 82.6% pass · 137k tests

See each bike's full report (trend, mileage curve, failure breakdown and rivals) on its own page.