Motorcycle MOT: What Gets Tested and Why Bikes Fail

Like cars, most motorcycles over three years old need an annual MOT in the UK (mopeds and motorcycles under 50cc first tested at four years). It's a legal roadworthiness check, not a full service — but it does catch a genuinely useful range of safety issues.

What's tested

The test broadly covers: lights and indicators, horn, brakes (front and rear, including brake fluid condition and lines), tyres and wheels, steering and suspension, the frame, chain and final drive, exhaust and emissions, mirrors, and the general condition of the bike including things like sharp edges or dangerous modifications. The tester also checks the VIN and registration plate match the paperwork.

Most common failure points

• •Worn tyres, below the legal 1mm minimum for the central three-quarters on a bike (deeper than a car's 1.6mm figure on the same central band, for motorcycles it's specifically 1mm)
• •A blown bulb or misaligned headlight beam
• •Excessively worn or maladjusted final drive chain
• •A leaking fork seal or visibly perished brake hose
• •Exhaust noise or emissions exceeding the permitted level, especially on modified exhausts

What happens if it fails

Defects are graded dangerous, major or minor. A dangerous or major defect is an outright fail, and you can't legally ride the bike on the road (except directly to a pre-booked repair or another MOT) until it's fixed and retested. Minor defects and advisories don't fail the test but should still be addressed — they're often the start of something that will fail next year if ignored.

Advisories vs failures

An advisory flags something worth monitoring — tyres nearing the legal limit, for example — without failing the test outright. Treat advisories as a heads-up rather than something to ignore completely; garages log them precisely because they tend to become failures at the next test if left alone.