HARLEY-DAVIDSON FAT BOY

1340cc Petrol Class 2

#1303 of 5426 overall #211 of 397 HARLEY-DAVIDSONs #254 of 465 cruiser bikes

88.9%

first-time pass rate

4.9%

failed outright

14,956

median miles at test

4,320

MOT tests, 2005–2025

Pass rate over time

first-time pass rate by test year · 2006–2025

The FAT BOY's first-time pass rate has fallen 10.1 points since 2006, 97.6% to 87.5%.

Pass rate by mileage

how the FAT BOY's first-time pass rate falls with the odometer · class average 84.9%

A low-mileage FAT BOY passes first time 89.7% of the time; by 50k that's 85.7%.

First-time pass rate by odometer reading at test, 10,000-mile bands for this model. Mileage is the strongest reliability signal. See the full curve.

What fails on a FAT BOY

failure defects by component group · advisories excluded

Component group	Defects	% of defects	vs all bikes
lighting and signalling	123	28.7	0.4×
lamps and reflectors	80	18.7	0.8×
brakes	67	15.7	0.3×
reg plates and vin	44	10.3	1.2×
tyres and wheels	24	5.6	0.3×
steering and suspension	21	4.9	0.2×
structure and attachments	20	4.7	0.6×
Identification of the vehicle	18	4.2	1.7×
fuel and exhaust	17	4	0.5×
tyres	14	3.3	0.4×

Defects recorded against failed normal tests, 2005–2025, grouped by DVSA inspection section. One test can record multiple defects. "vs all bikes" is how often this model's tests record a defect in the group, as a multiple of the all-bike rate.

How rivals compare

same type, similar capacity, high test volume

On first-time pass rate the FAT BOY beats 2 of its 4 closest rivals (HARLEY-DAVIDSON FLSTF, HARLEY-DAVIDSON FLSTC, HARLEY-DAVIDSON XL1200C).

HARLEY-DAVIDSON FLSTF 88.9% pass · 30.1k tests HARLEY-DAVIDSON FLSTC 89.4% pass · 23.7k tests HARLEY-DAVIDSON XL1200C 88.4% pass · 15.7k tests HARLEY-DAVIDSON FXDWG 88.7% pass · 14.6k tests

Rivals share this bike's type and sit within ±30% of its engine capacity, ≥ 5,000 tests. Card colour = better/worse first-time pass rate than the FAT BOY.

Pass rate by registration year

how each model-year cohort fares · registration year from first use date

Best year to buy used: 2003 (93.2% pass). Weakest: 2008 (78.9%).

First-time pass rate by the year each bike was first registered (cohorts with ≥ 50 tests). Older cohorts are survivors: the worst examples have already left the road, which tends to lift the earliest years.

HARLEY-DAVIDSON FAT BOY FAQ

answers computed from the data above · terms in the glossary

Is the HARLEY-DAVIDSON FAT BOY reliable?

The HARLEY-DAVIDSON FAT BOY is more reliable than average for its class: 88.9% of its 4,320 MOT tests (2005–2025) passed first time, against a class average of 84.9%. That ranks it #1303 of 5426 models.

What does a FAT BOY fail its MOT on most?

lighting and signalling — 29% of all defects recorded against failed FAT BOY tests.

What is the best year of FAT BOY to buy used?

By first-time pass rate, 2003-registered examples do best (93.2%) and 2008 worst (78.9%). Condition and history still trump the year.

How many miles will a FAT BOY last?

The median FAT BOY shows 14,956 miles at test, and examples around 50k miles still pass 85.7% of the time — mileage alone rarely kills one.