MOT failure rate and common problems for the Harley-Davidson Motor, and how to check your own car by registration.
Updated 05 September 2026.
Harley-Davidson Motor MOT failure rate
What a Harley-Davidson Motor fails its MOT on, and the part that fixes each.
What it fails on, and why
A missing, damaged, dirty or incorrectly-spaced number plate, or one using the wrong font, will fail. A replacement plate is inexpensive.
Exhaust failures cover leaks, insecure mountings and emissions over the limit. A blowing exhaust, a failed lambda reading or a diesel that smokes beyond the limit will fail.
Brake failures cover worn pads and discs, an imbalance between wheels, corroded or scored discs, or a binding caliper. Braking efficiency is measured on a rolling road, so a spongy or pulling brake shows up as a low reading.
The parts that fix each
If your car has just failed, you have 10 working days to fix the items and get a free partial retest. Confirm the exact fitment against your registration or VIN before buying.
Other models
Questions and answers
What is the MOT failure rate of the Harley-Davidson Motor?
It fails 9.6% of its MOT tests across the DVSA record, from 73 tests.
What do these cars fail their MOT on most?
The most common failure area is registration plate, at 42.9% of this model's failures.