If you buy used motorcycle parts, you're often on thin ice. Between a real bargain and dangerous scrap there's sometimes only one click. If you want to save money on repairs without compromising on safety, you have to be able to assess parts remotely. In the second part of our maintenance series we look at used parts: how to avoid bad buys and scams, with measurable facts, visible clues and a close look at the seller rather than luck.
Reading the listing: what the seller reveals about themselves
Before you look more closely at a fork or engine, the check starts with the seller and their ad. A listing on eBay or classifieds sites doesn't just show the goods. It also says a lot about how carefully the previous owner treats technology. Someone who looks after their bike doesn't photograph parts on bare concrete. Someone who carelessly snaps expensive brake calipers or precision components in a dark corner probably wasn't very careful with maintenance and storage either.
Pay attention to the wording. Phrases like "ran perfectly until removed" are often a protective claim to avoid giving any guarantee of function. Someone who knows their stuff will instead give you the exact donor vehicle, the VIN and documented mileage. If the seller dodges specific questions about service intervals or storage, walk away, however cheap the part is. The cheapest parts are often the ones that cost you most in the end through follow-up damage.
Used forks: the invisible danger of bent tubes
On a motorcycle both wheels have to track exactly in line. If you buy used fork legs, in the worst case you get the remains of a head-on crash. The tricky part: even a bend of a few tenths of a millimetre ruins the response and destroys the seals within a few kilometres. You can't put a dial gauge on a photo. The light-line trick helps here: look at the reflections on the chrome of the stanchions. If the line of light stays straight and doesn't distort when the tube is rotated, that's a good sign the tube is straight.
Pitting is just as critical. These are tiny, often pinprick-sized rust spots from stone chips or long periods standing in damp sheds. When these bumps run through the seal lips, they act like sandpaper. A used fork leg with pitting in the working area is practically scrap, because a proper repair (grinding and re-chroming) is often hardly cheaper than a new part. Be strict here and ask for sharp close-ups, ideally macro shots, of the sliding surfaces.
Used wheels: spotting dents and hairline cracks
Wheels are among the most heavily stressed parts of a motorcycle. A dent in the rim, for example from a deep pothole or a kerb, causes dangerous handlebar shake at high speed. With cast wheels there are also hairline cracks. These form mainly at the spoke roots, where the stress is highest. If you can inspect the wheel in person, an old but effective test helps: the ring test. Hang the wheel freely on a string and tap it lightly with a plastic hammer or a large screwdriver handle. An intact wheel rings clearly and long, like a bell. A dull, short "plop" can indicate a crack in the material. Then the wheel is a real safety risk and stays with the seller. The ring test is only a rough indicator, though, not crack testing: for expensive wheels a check at a specialist workshop is worth it if in doubt.
Used electronics: checking ECUs and regulators
Used electronics are the biggest gamble for mechanics on a budget. You can't see an internal fault in an ECU or a regulator rectifier. So you have to rely on other senses. The smell test is surprisingly reliable. Components that died from overvoltage or a short circuit often smell sharply burnt long afterwards.
Look at the connectors too. Are the contacts greenish and oxidised, or do they show heat discolouration (bluish)? The latter points to severe overheating. Then not only the part itself is suspect, but probably also the wiring loom in the donor vehicle. Private sellers almost always exclude returns on electronics. So it's best to buy such parts from commercial used parts dealers. As a consumer in Germany you have a statutory warranty there, which the dealer may only shorten to a minimum of one year for used goods, and only if they point this out to you specifically.
The E-mark trap: is the part legal for your motorcycle?
With exhausts or lights, many rely on the embossed E-mark. That's exactly where a legal trap lies: in Germany, if a modification worsens the noise behaviour, the operating permit lapses under § 19 StVZO, and the police will notice at the latest during a check. The E-mark only says that the part has type approval. It doesn't say whether it's approved for your motorcycle model. A silencer from a Suzuki GSX-R might fit your Honda and have an E-mark too. But if your Honda isn't listed in the certificate, it's still illegal on it.
When buying used, also check the dB killers. Many previous owners drill them out or remove them completely, and that's immediately noticed at a check. Tampered rivets or weld spots on the end cap are clear warning signs. A reputable seller can give you the matching approval or the manufacturer's certificate (for example as a PDF), stating the approval for your model in black and white.
Frequently asked questions about used motorcycle parts
How can I tell that a part comes from a crashed motorcycle?
Look for one-sided marks. Scrape marks on the underside of footpegs, on bar ends or axle nuts are clear signs. Chipped paint at the welds of a frame or bracket also shows that the metal briefly deformed under great force. Such parts are structurally weakened.
Is a used engine with high mileage a risk?
Mileage alone isn't a reason to rule it out if the maintenance is documented. A long-distance engine with 80,000 km can be in better shape than a short-trip engine with 15,000 km that never got properly warm. Ideally ask for a video of a cold start. Watch for blue smoke (oil consumption) or mechanical rattling from the cylinder head.
Can I use used brake hoses?
Clearly no. Rubber hoses age and swell from the inside. Many manufacturers specify replacement after a few years in their service schedules, check your manual. Buying used rubber hoses therefore makes no sense. The only exception is high-quality braided steel lines without kinks or chafing on the metal braid.
What do I need to know legally when buying privately?
In Germany, private sellers usually exclude liability for defects. However, the seller can't rely on this if they fraudulently concealed a defect or gave a guarantee. If a seller fraudulently conceals crash damage (German law), you can still assert your rights or challenge the purchase contract for fraudulent misrepresentation (§ 123 BGB). So always save the original listing and the entire message history as evidence.
Summary
Hunting for used spare parts is more than saving money. It's a good school for every mechanic. With the checks in this article you turn the marketplace gamble into a technical decision. A shiny photo often only shows the surface. A part's real story lies in the details: the straight line of light on the chrome, the clear ring of a tapped wheel or the matching E-mark on a silencer.
As a mechanic on a tight budget, you mainly need patience and persistence. A supposed bargain that turns out to be a crash part on closer inspection isn't a missed deal but avoided damage. Your goal isn't the cheapest part, but the one with the best ratio of remaining life to price. Over time you'll develop a feel for whether a component is OK. That helps you when buying online as well as with every inspection of your own bike.
However, the best spare part won't help much if you look after it wrongly or treat it with the wrong chemicals. The wrong penetrating oil can ruin a fork you searched hard for within a few weeks. That's why the next part of our series is about an often underestimated topic in the workshop: chemicals. We explain why WD-40 isn't a lubricant, how brake cleaner attacks plastics and which substances your motorcycle really needs to last a long time.
Sources
- § 444 BGB exclusion of liability (German law, German)
- § 123 BGB avoidance for deceit or duress (German law, German)
- § 476 BGB deviating agreements in consumer sales (German law, German)
- § 19 StVZO granting and validity of the operating permit (German law, German)
Last checked: September 2026. Rules can change.