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Common motorbike MOT fails you can fix at home

Lights fail more motorbike MOTs than anything else, and most of what fails can be fixed on the driveway. Here's what DVSA's data says, and how to avoid the easy ones.

Last checked against GOV.UK: 2 November 2026

What bikes fail on

DVSA publishes MOT fail data for motorcycles (classes 1 and 2). In the year from April 2025 to March 2026, 13.4% of motorbikes failed their first test. This is the share of all tests that had a fail in each area:

Area	Tests with a fail here
Lamps and reflectors	7.31%
Brakes	3.16%
Structure and attachments (incl. chain, exhaust)	2.08%
Suspension	1.97%
Tyres	1.85%
Steering	1.24%
Identification (plate, VIN)	0.92%
Wheels	0.17%
Horn	0.06%

Lights are more than twice as common as anything else, and most light fails are a five-minute fix.

The fixes you can do at home

Bulbs, lenses and indicators

Check every lamp: headlamp on dip and main beam, sidelight, tail light, number plate light and all four indicators. Then check the stop lamp twice, once with the front lever and once with the rear pedal. On bikes first used from 1 April 1986 both must work it. A rear brake light switch that's out of adjustment is a classic fail; most can be adjusted with a nut on the switch body. Indicators must be amber and flash 60 to 120 times a minute: aftermarket LED indicators without the right relay or resistor often flash too fast. While you're there, check no lens is cracked or missing.

Rear reflector

A tail tidy kit can remove the red rear reflector. The bike needs one, red, on the centre line and facing straight back. Reflective tape doesn't count.

Horn

It must work and give one continuous tone. If it's weak, check the connections and the battery charge.

Tyres

Measure the tread with a depth gauge. Over 50cc you need at least 1.0 mm across a continuous band covering three-quarters of the tread width, all the way round. Look for cuts, bulges and exposed cords too. Tyre fails are often dangerous defects, not just majors, so replace rather than hope.

Chain

Set the slack to the figure in your manual, measured at the tightest point of the chain. Too tight fails as well as too loose. If the chain has tight spots, or the sprocket teeth are hooked, it needs replacing rather than adjusting. Check the chain guard is secure.

Brakes

Look at the pads from below the calliper: below 1.0 mm of friction material is dangerous. Top up fluid to between the marks with the type printed on the cap, and look for weeps at the master cylinder, hose ends and callipers. A spongy lever needs bleeding or a fluid change before the test.

Number plate

Two lines, black on yellow, the right font and spacing, and securely fixed near vertical. Small "show plates", italic or stylised fonts and fixing screws that change how a character reads all fail. Plates fitted after 1 September 2021 need the BS AU 145e marking and characters in a single shade of black.

Exhaust noise

A silencer marked "not for road use" or "track use only" is a major defect, as is a loud system. If you've fitted a race can, refit the road-legal one for the test, and keep it on.

What about mirrors?

Mirrors aren't part of DVSA's motorcycle MOT inspection manual, so they won't fail the test. Fit good ones anyway: you need them for lifesavers, lane changes and filtering.

Leave these to a garage

Corroded or leaking brake pipes and seized callipers.
Steering head or wheel bearings with play or notchiness.
Leaking fork seals or a failed shock.
Frame or swingarm corrosion or damage.

Fix it before the test, not after

Tickover reminds you a month before your MOT and lists the advisories from last time, so you can sort the easy fails at home first.

Get early access

Quick answers

What is the most common reason motorbikes fail the MOT?

Lamps and reflectors. In DVSA's figures for April 2025 to March 2026, 7.31% of motorcycle tests had a lighting fail, more than twice any other area.

Will a tail tidy fail the MOT?

It can if it removes the red rear reflector or moves the plate or plate lamp so they don't meet the rules. Fit a red reflector on the centre line facing the rear.

Do mirrors get checked on a motorbike MOT?

No. Mirrors are not in the motorcycle MOT inspection manual, but you should still have good ones fitted.

Can a loud exhaust fail the MOT?

Yes. Exhaust noise clearly above what you'd expect is a major defect, and so is a silencer marked not for road use.

Does a too-tight chain fail the MOT?

Yes. An excessively tight chain is a major defect, the same as an excessively loose one.

Related guides

Sources

This guide is general information, not legal advice. Rules can change: check GOV.UK before you act. Tickover is independent and not affiliated with the DVLA or DVSA.