Norton Model 50 vs Yamaha RD350

The Norton Model 50 passes its MOT first time more often than the Yamaha RD350: 92.6% vs 86.3%, a 6.3-point lead.

MOT reliability, side by side

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

Metric	Norton Model 50	Yamaha RD350
First-time pass rate	92.6%	86.3%
Outright fail rate	2.4%	6.6%
Engine size	350cc	347cc
Rank among all models	#367 of 5428	#2120 of 5428
Median miles at test	30,636	23,256
MOT tests analysed	501	19,574
Most common failure	tyres and wheels	lighting and signalling

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 Model 50	Yamaha RD350
Lights & signalling	0.6%	3.2%
Steering & suspension	0.8%	2.5%
Brakes	0.2%	2.7%
Tyres & wheels	1.4%	0.9%
Fuel & exhaust	0.2%	0.4%
Structure & body	0.2%	0.4%
Drive system	0%	0.5%

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 Model 50	Yamaha RD350
2006	90.2%	79.9%
2007	90.4%	81.2%
2008	94.4%	79.7%
2009	88.9%	80.6%
2010	89.1%	81.9%
2011	95.7%	82.2%
2012	89.4%	84.7%

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 Model 50	Yamaha RD350
0k-10k miles	94.5%	88.9%
10k-20k miles	85.4%	87.5%
20k-30k miles	87.5%	85.5%
30k-40k miles	92.2%	85.3%
40k-50k miles	91.8%	83.7%
50k-60k miles	100.0%	83.0%

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

Norton Model 50 vs Yamaha RD350 FAQ

answers computed from the data above · terms in the glossary

Which is more reliable, the Norton Model 50 or the Yamaha RD350?

The Norton Model 50 passes its MOT first time more often than the Yamaha RD350: 92.6% vs 86.3%, a 6.3-point lead. An MOT checks roadworthiness items, not engine or gearbox internals.

What does the Norton Model 50 fail its MOT on most?

Tyres & wheels: 1.4% of Norton Model 50 MOT tests failed on it, then steering & suspension (0.8%).

What does the Yamaha RD350 fail its MOT on most?

Lights & signalling: 3.2% of Yamaha RD350 MOT tests failed on it, then brakes (2.7%).

Which holds up better at high mileage, the Norton Model 50 or the Yamaha RD350?

At 50k-60k miles the Norton Model 50 passes first time more often: 100.0% for the Norton Model 50 vs 83.0% for the Yamaha RD350.

NORTON MODEL 50 92.6% pass · 501 tests YAMAHA RD350 86.3% pass · 19.6k tests

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