Harley-Davidson FAT BOB MOT pass rate and common failures
Harley-Davidson FAT BOB motorcycles pass the MOT 88.94% of the time, measured across 434 tests in the DVSA record. A further 5.3% passed only after a defect was put right at the test station.
What to check before the MOT
Built from this model's own failure record, not general advice.
- Start with remains on when the brakes are released - it accounts for 64% of failed tests on this model.
- Then check missing and does not conform to the specified requirements, the next two most common reasons.
- The most common advisory is noise is clearly in excess of that emitted by a similar motorcycle fitted with a standard silencer in average condition (23.3% of all tests) - not a failure, but money you will spend sooner or later.
- Average recorded mileage at test is 15,721 miles, which is the number to compare any advert against.
Pass rate by age
A single pass rate hides the most useful thing in this data: how the same model behaves at three years old and at fifteen.
| Age at test | Pass rate | Tests | |
|---|---|---|---|
| 6-10 years | 90.03% | 311 | |
| 11-15 years | 85.34% | 116 |
Why the Harley-Davidson FAT BOB fails
Share of failed tests on this model where the item was recorded. One test can fail on several items, so the column does not add up to 100%.
| # | Item | Of failures | Tests | |
|---|---|---|---|---|
| 1 | Remains on when the brakes are released | 64% | 16 | |
| 2 | Missing | 44% | 11 | |
| 3 | Does not conform to the specified requirements | 24% | 6 | |
| 4 | Not working | 24% | 6 | |
| 5 | Does not illuminate by the operation of both brake controls | 16% | 4 | |
| 6 | Insecure | 12% | 3 | |
| 7 | Switch does not operate in accordance with the requirements | 12% | 3 | |
| 8 | Too high | 12% | 3 | |
| 9 | Inoperative in the case of a single lamp or all lamps | 8% | 2 | |
| 10 | Not releasing correctly | 8% | 2 |
Most common advisories
Not a failure and not a legal requirement to fix - but an advisory that repeats year after year is money the next owner spends.
| # | Item | Of all tests | Tests | |
|---|---|---|---|---|
| 1 | Noise is clearly in excess of that emitted by a similar motorcycle fitted with a standard silencer in average condition | 23.3% | 101 | |
| 2 | Tread depth is below minimum requirements of 1.0mm | 4.4% | 19 | |
| 3 | Less than 1.0 mm thick | 3.7% | 16 | |
| 4 | Indicates excessive fluctuation of brake effort | 2.1% | 9 | |
| 5 | Excessively binding | 1.4% | 6 | |
| 6 | Has excessive play | 1.2% | 5 | |
| 7 | Excessively stiff or notchy | 0.9% | 4 | |
| 8 | Has a serious fluid leak | 0.9% | 4 | |
| 9 | Tread not clearly visible | 0.7% | 3 | |
| 10 | Attachment bracket/mounting insecure | 0.5% | 2 |
Harley-Davidson FAT BOB for sale
No Harley-Davidson FAT BOB in stock at the moment - 48 other Harley-Davidson bikes are advertised.
Similar bikes compared
Models of comparable capacity, so the comparison means something.
| Model | Tests | Pass rate | Avg mileage | |
|---|---|---|---|---|
| BMW R1250 · 1,254cc | 6,764 | 96.17% | 17,373 | |
| Triumph BONNEVILLE 1200cc · 1196-1200cc | 5,527 | 91.62% | 8,342 | |
| Yamaha XJR1300 · 1,251cc | 3,805 | 90.43% | 26,274 | |
| BMW K SERIES 960-1393cc · 960-1393cc | 3,695 | 89.23% | 38,457 | |
| BMW R 1250 GS ADVENTURE TE · 1,254cc | 2,946 | 96.33% | 12,375 | |
| BMW R 1250 GS TE · 1,254cc | 2,512 | 96.46% | 12,060 |
Source: DVSA MOT testing data, 2025 · updated Aug 2026 · licence and method