How to inspect a used dirt bike before you buy

The inspection starts with the messages, not the driveway. A few questions asked beforehand will save you a wasted drive, and the answers themselves tell you something about the seller.

• Ask them not to start or warm the bike before you arrive. This is the single most useful request you can make, and the reason is in the next section.
• Ask for the VIN and engine number. A seller with nothing to hide will send them.
• Ask what has been replaced and when, and whether there are receipts.
• Ask whether the hour meter reading is total hours or hours since a rebuild — those are very different claims.
• Ask where you will be inspecting it. A home address is a better sign than a car park.

Worth taking with you: a torch, a rag, gloves, and someone else if you can. A second person notices things you miss and makes it much easier to hold your ground on price.

A cold engine shows you more than a warm one. None of the following diagnoses a fault on its own — they are things to notice and ask about, and several together are worth more than any one.

• How much effort it takes. Several kicks or a long crank on a bike the seller describes as perfect is worth asking about.
• Smoke at startup, and whether it clears. Blue smoke suggests oil burning. White smoke that keeps going after warm-up can mean coolant entering the engine. A two-stroke will smoke on its own — the question is whether it settles.
• Rattles and knocks in the first seconds, and whether they fade as oil circulates.
• Whether it holds an idle once warm, or needs constant throttle to stay running.

Before you look at anything mechanical, confirm the bike in front of you is the bike in the advert.

• Check the VIN stamped on the frame against the advert and any paperwork. Photograph it.
• Check the engine number too. An engine swap is not automatically a problem, but it should be disclosed.
• Look closely at the stamping itself. Grinding marks, uneven depth or mismatched fonts around the numbers are a reason to stop.
• If it is registered or on recreational registration, check the paperwork matches the frame number and the person selling it.

A register search only tells you about the bike whose VIN you searched, so this step is what makes the search meaningful at all. If the numbers don't match the advert, nothing else on this page matters.

Frame damage is the hardest thing to fix and the easiest thing to hide under new plastics.

• Look along the frame from the front and the rear for anything that isn't straight or symmetrical.
• Inspect the welds around the headstock and where the frame rails meet the engine cradle. Look for cracks and for weld that looks different from the factory beads elsewhere.
• Check the subframe and the footpeg mounts, which take the hit in a crash.
• Fresh frame paint on an otherwise well-used bike deserves a direct question about what is underneath it.
• For steering head bearings: hold the front brake and rock the bike forwards and backwards. A knock you can feel through the forks usually means the bearings need attention.

Suspension is a normal wear item, so finding work needed here is not a reason to walk away — it's a reason to adjust what you'll pay.

• Fork seals: look for oil on the fork lowers or a wet line down the stanchions. Push down on the front end and check again.
• Run a fingernail down the stanchions. Pitting or deep scratches mean more than a seal kit.
• Rear shock: check the shaft and body for oil, and ask when it was last serviced.
• With the rear wheel off the ground, grab the swingarm and move it side to side. Play there points at swingarm or linkage bearings.
• Ask when the linkage was last stripped and greased. A seller who knows the answer has usually looked after the rest of it too.

You are not going to pull the engine apart in a driveway. What you can do is collect signs, and treat several small ones as more meaningful than any single reading.

• Coolant: look in the radiator when cold. Oily or milky coolant can indicate a head gasket problem.
• Oil on a four-stroke: check the level and colour, and look at the magnetic drain plug if the seller is willing. Fine paste is normal wear; visible metal flakes are not.
• Radiators: bent fins, crushed cores or a radiator sitting out of line point to an impact. A leak on its own does not — seams weep with age and vibration, and stones puncture cores. Treat visible deformation and a leak as two separate findings, and ask about each.
• Listen for top-end noise once warm, and for anything that changes with engine speed rather than road speed.
• Ask for a compression figure if the seller has one, and compare it against the service manual for that exact model rather than any general number.

• Work through every gear, including the ones people skip. Jumping out of a gear under load is expensive.
• Clutch: check the lever has free play and that take-up feels smooth rather than grabbing. Correct free play and whether the clutch is cable or hydraulic differ by model, so check the figure in that bike's manual rather than a general one. Resist the stationary stall test people describe — deliberately loading a clutch puts heat through a part that isn't yours yet, and slip is easier to feel on a hot engine during a ride.
• Chain: look for tight spots by rotating the wheel and checking tension in several places. Pull the chain away from the rear sprocket — if it lifts well clear of the teeth, it's worn.
• Sprocket teeth should be symmetrical. Hooked or pointed teeth mean the chain and both sprockets are due.

Drivetrain wear is also a useful cross-check on the seller's story. A heavily worn chain and hooked sprockets on a bike advertised as barely used is a contradiction worth raising politely and directly.

• Spin each wheel and watch the rim for wobble, and look for dents on the rim edges.
• Grab each wheel at the top and rock it against the axle. Play means wheel bearings.
• Tap the spokes. Consistent tones suggest even tension; a dull one means a loose spoke.
• Check brake pad material left, and look at the discs for scoring or a lip at the outer edge.
• Squeeze the front brake and check the lever doesn't come back to the bar.

If a seller won't let you take the seat or side panel off to look, that refusal is your answer.

Plenty of private sellers won't allow a test ride, and that isn't unreasonable given the risk to them. If that's the case, at least ask to let it idle up to temperature and to sit on it with the engine running while you work the clutch and gears.

• If you do ride, agree first what happens if something breaks or you drop it.
• Feel for the clutch slipping as the engine gets hot, which is when it shows up.
• Check it tracks straight with your hands relaxed.
• Use the brakes hard enough to feel whether they actually work.

• The engine was warm when you arrived and the seller is vague about why.
• They won't provide the VIN, or the stamping looks tampered with.
• A rebuild is claimed but there are no receipts and no detail about what was actually replaced.
• New plastics and fresh paint on a bike that is worn everywhere you can't see.
• Pressure to pay a deposit before you've seen it, or a price well under market attached to an urgent story.
• Anything about the sale that has to happen away from a home address, in a hurry, in cash only.

None of these are proof of anything on their own. Two or three together is a pattern, and there will be another bike.

Negotiate on what you found rather than on a round number. Specific, evidenced points — a chain and sprocket set, fork seals, a set of tyres — are much harder to argue with than an opening offer.

Do the register search before any money changes hands, not after. A bike with finance owing against it can still be a problem for you after you've bought it, and that is not something an inspection can reveal.