By Sarah Tawton
Motorcyclists have been urged to exercise caution before splashing out on a second-hand bike this summer.
Vehicle information experts at HPI say one in five bikes checked by the company has a hidden history.
This could include being written off by an insurance company or having outstanding finance recorded against it, HPI said.
And with one in five vehicles stolen in the UK reported to be a motorcycle, buyers are particularly at risk of unwittingly purchasing a stolen bike.
Daniel Burgess, managing director at HPI, said: "Unfortunately, whilst cars have become more difficult to steal, motorcycles remain an easy target for thieves.
"Bikes are smaller and less secure than cars, making them easier to steal and move on - with many thieves simply picking the bikes up from the street and putting them in the back of a van."
Mr Burgess added: "Buying a stolen bike means consumers could lose the bike and the money they paid for it when it's returned to the owner."
In addition, one in 10 motorbikes checked by HPI still has finance on it, meaning it still legally belongs to the relevant finance house. As a result, any buyers could face losing the bike and the money they paid for it.
Meanwhile, the same proportion of motorbikes have also been written off by an insurance firm, creating a serious safety hazard if they have not been properly repaired.
HPI has published new guidelines for motorcyclists to help them find the right bike this summer.
The firm is advising potential buyers to do their research by going online to find out the market value of the bike and the price they should be paying. Getting an insurance quote can also help gauge whether or not a bike is affordable.
When buying a bike privately, HPI says buyers should always arrange to meet the seller at their home address, and make sure this is the one listed on the V5C document.
The bodywork should be examined for any scratches or dents, particularly at the rear of the tank, engine cases, foot pegs and exhaust pipes as these could be a sign the bike has been dropped. By making sure they look at the bike in daylight and in good weather, the buyer will make it easier for themselves to spot any potential defects.
Other aspects to check include the condition of the tyres and the tread, which should be a minimum depth of 1mm. When checking the engine, HPI recommends starting it from cold, as this makes it easier to spot starting problems or excessive smoke.
Buyers should also make sure that both sets of keys fit the petrol cap and seat lock as well as the ignition, and test drive the bike to check that the gears are in full working order.
Any buyers who are concerned about their purchase can get an HPI history check, which will tell them if the bike has been stolen, written off, is on outstanding finance or has a mileage discrepancy.