Derbi Mulhacen 659 vs Yamaha FZS600

The Derbi Mulhacen 659 passes its MOT first time more often than the Yamaha FZS600: 87.4% vs 82.6%, a 4.8-point lead.

MOT reliability, side by side

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

Metric	Derbi Mulhacen 659	Yamaha FZS600
First-time pass rate	87.4%	82.6%
Outright fail rate	7.3%	10.6%
Vs comparable bikes (age & mileage adjusted)	-0.4 pts	-0.8 pts
Engine size	659cc	599cc
Rank among all models	#1787 of 5428	#3052 of 5428
Median miles at test	5,330	21,612
MOT tests analysed	206	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	Derbi Mulhacen 659	Yamaha FZS600
0k-10k miles	90.9%	89.6%
10k-20k miles	82.7%	85.5%

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

DERBI MULHACEN 659 87.4% pass · 206 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.