Moto Guzzi 850 T4 vs Suzuki GSF600

The Moto Guzzi 850 T4 passes its MOT first time more often than the Suzuki GSF600: 86.2% vs 77.3%, a 8.9-point lead.

MOT reliability, side by side

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

Metric	Moto Guzzi 850 T4	Suzuki GSF600
First-time pass rate	86.2%	77.3%
Outright fail rate	7.2%	14.2%
Vs comparable bikes (age & mileage adjusted)	+2.8 pts	-6.1 pts
Engine size	844cc	599cc
Rank among all models	#2148 of 5428	#4013 of 5428
Median miles at test	50,366	21,080
MOT tests analysed	487	143,023
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 test year

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

Test year	Moto Guzzi 850 T4	Suzuki GSF600
2008	83.3%	78.4%
2009	82.4%	75.8%
2010	76.5%	75.8%
2011	84.8%	76.1%
2012	85.7%	75.9%
2014	87.1%	75.0%
2016	93.5%	76.1%
2017	87.5%	77.0%

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	Moto Guzzi 850 T4	Suzuki GSF600
0k-10k miles	86.5%	86.8%
10k-20k miles	88.9%	80.1%
20k-30k miles	94.2%	75.2%
40k-50k miles	92.0%	69.4%
50k-60k miles	78.3%	68.3%

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

MOTO GUZZI 850 T4 86.2% pass · 487 tests SUZUKI GSF600 77.3% pass · 143k tests

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