Buying a written-off motorbike: what Cat S and Cat N mean

A written-off motorbike is not necessarily a wrecked one. That single misunderstanding costs buyers money in both directions, and it is worth clearing up before anything else on this page.

People hear "write-off" and picture a bike folded round a lamp post. In practice, an insurance write-off is an accounting decision, not a description of damage. It means the insurer worked out that repairing the machine would cost more than it was worth to them, so they paid out and disposed of it instead. On a bike, that calculation tips over surprisingly early.

Which means two things. A bike with a write-off marker may be perfectly sound and a good value. And a bike with a write-off marker may be structurally compromised and dangerous. The category tells you which conversation you are having, and this check tells you the category.

Why bikes get written off so easily

The economics on two wheels are unforgiving in a way they are not on four.

Consider a five-year-old middleweight worth around three thousand pounds. It goes down at walking pace in a car park. Nobody is hurt and the engine never stops running. What breaks: both fairing panels, a mirror, a lever, an indicator, the exhaust can is scored, the engine casing is scuffed through, and the bar end and footpeg hanger are ground down.

Every one of those is a genuine part with a genuine price. Fairing panels on a modern sports or sports-touring bike run to several hundred pounds each before paint, and paint on a multi-stage metallic is not cheap either. A can might be six hundred. Casings mean splitting things open, which means labour. Add a couple of days of workshop time.

The bill lands somewhere near two thousand pounds on a bike worth three. The insurer looks at that, decides it is not worth the risk of hidden damage they have not found yet, and writes it off.

Nothing structural happened. The frame is straight, the forks are true, the engine is untouched. On a car, the equivalent event is a scraped wing and a wing mirror, and the insurer would repair it without a second thought. The difference is that a car's expensive parts are mostly protected by its cheap parts, and a bike's expensive parts are all on the outside.

The four categories

Two older categories still appear on bikes registered before October 2017, when the system changed.

Cat C meant repairable, but the repair cost exceeded the bike's value. Broadly comparable to today's Cat S in effect, though it was defined by cost rather than by the type of damage.

Cat D meant repairable at a cost below the bike's value, where the insurer chose not to repair anyway. Often the lightest of the historic markers.

A bike carrying a legacy C or D marker keeps it permanently. It does not get reclassified, and it will show on any check for the rest of the machine's life.

The Cat N problem nobody warns you about

Here is the detail that makes this check worth paying for.

When a machine is written off as Cat S, the insurer is required to notify the DVLA and the original V5C is destroyed. Before it can legally return to the road it has to be re-registered, which means applying to the DVLA for a replacement logbook. The replacement carries a permanent annotation recording the Cat S history, so the paperwork itself tells the story to every future buyer.

Cat N works differently, and this is the part worth knowing.

Because the damage is classed as non-structural, there is no re-registration requirement. The existing V5C stays with the machine. No new document, no annotation, nothing on the face of the paperwork to suggest anything ever happened.

So a Cat N bike can be presented to you with an entirely clean, entirely genuine logbook. The seller may not even know, particularly if they bought it themselves without running a check. The only place the record reliably exists is the insurance industry register, which is not public and which every provider pays to query.

That is the specific gap this check closes. You can inspect a Cat N bike carefully, read the V5C line by line, and find nothing at all.

If you are looking at a Cat S, the reverse applies and it is worth using. Ask to see the logbook. A genuine repaired Cat S carries the annotation. A machine a history check says is Cat S, presented with an unannotated logbook, is a machine whose paperwork and record disagree.

When the seller doesn't know

This happens more often than you would expect, and it follows directly from the logbook gap above.

Someone buys a bike privately without running a check. It carries a Cat N marker from two owners ago, the V5C was never surrendered, and nothing in the paperwork mentions it. They ride it for four years, look after it properly, and advertise it in good faith as a clean bike. Your check then tells you something they did not know about their own machine.

Tell them plainly and show them. Most people react with genuine surprise.

Judge the reaction rather than the marker. Someone who is shocked and starts asking questions is telling a different story to someone who becomes defensive.

The price still has to move. However blameless the seller is, the bike is worth less than a clean example and your own buyer will find the same marker in three years.

If your own bike gets written off

When an insurer writes off your bike they pay you its market value and take ownership of the machine. You can usually ask to buy back a Cat S or Cat N yourself, often for a fraction of the payout, which is how a large number of repairable write-offs return to the road. That buy-back is entirely legal and entirely normal.

What it means for a buyer is that the person selling you a repaired Cat S may well be the same person who crashed it, repaired it, and knows exactly what was done. That is often the best-informed seller you will find. Ask them directly what happened and what they replaced.

What a write-off does to value and insurance

Value. A repaired write-off is worth meaningfully less than an equivalent clean example, and the gap does not close with age. The two categories are not affected equally. Trade guidance puts the reduction at roughly 15 to 25 per cent for Cat N and 25 to 40 per cent for Cat S, reflecting the structural repair and the extra paperwork involved.

Those are broad ranges and the specific model matters. What holds in every case is that the discount you fail to negotiate now is one you absorb when you sell.

Insurance. Cover is available on repaired Cat S and Cat N bikes, but the pool of insurers willing to write it is smaller and premiums are usually higher. Some insurers decline outright. If you are considering one, get a quote before you commit rather than after.

Buying a Cat S or Cat N bike sensibly

Find out what happened. Ask the seller directly and see whether the story matches the category. Cosmetic fairing damage explains a Cat N. It does not explain a Cat S.

Get it inspected, properly, by someone independent. Not the seller's mate. On a Cat S in particular, someone needs to confirm the frame is straight and the repair was done to standard.

Check the repair yourself as well. Look for mismatched paint under daylight, panel gaps that do not line up, replacement fasteners that are newer than their neighbours, overspray on rubber and cables, and welding that has been painted over rather than finished.

Look at the MOT record afterwards. A bike repaired badly tends to say so at test time. Alignment, suspension and brake advisories appearing shortly after the write-off date are worth taking seriously.

Price it as what it is. A repaired write-off at clean-bike money is a bad deal regardless of how good the repair was.

The write-off category is one line of a longer record. A full motorbike check returns it alongside outstanding finance, theft markers and the mileage trail, which is the combination that tells you what a repaired bike is really worth.

FAQs

Is it legal to ride a Cat S or Cat N motorbike?

Yes, once it has been repaired and is roadworthy. Cat S bikes must be re-registered with the DVLA before returning to the road. Cat N bikes need no re-registration. Neither category requires a special test beyond a valid MOT.

Does a write-off marker ever come off the record?

No. It stays with the bike permanently, including the legacy Cat C and Cat D markers from before October 2017.

Can a Cat B bike be sold?

The frame cannot legally return to the road and must be destroyed. Parts may be salvaged and sold. A complete Cat B machine being advertised as a runner is a serious warning sign.

The seller says it was only cosmetic damage. Should I believe them?

Possibly, and the category will tell you. Cosmetic damage is consistent with Cat N. If the record shows Cat S, the damage was structural regardless of what the advert says.