Bsa B50 vs Yamaha FZS600

The Bsa B50 passes its MOT first time more often than the Yamaha FZS600: 91.0% vs 82.6%, a 8.4-point lead.

MOT reliability, side by side

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

Metric	Bsa B50	Yamaha FZS600
First-time pass rate	91.0%	82.6%
Outright fail rate	2.5%	10.6%
Vs comparable bikes (age & mileage adjusted)	+5.7 pts	-0.8 pts
Engine size	500cc	599cc
Rank among all models	#682 of 5428	#3052 of 5428
Median miles at test	5,324	21,612
MOT tests analysed	279	136,558
Most common failure	lighting and signalling	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.

"Vs comparable bikes" is the first-time pass rate minus the rate expected for each bike's own mix of age, mileage and test class, in percentage points: positive means better than comparable bikes. How this works.

Pass rate by mileage

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

Mileage	Bsa B50	Yamaha FZS600
0k-10k miles	91.5%	89.6%
10k-20k miles	92.5%	85.5%

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

BSA B50 91.0% pass · 279 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.