A German pensioner was arrested after fitting a chainsaw engine to his wife's bicycle and hurtling down the road at 40mph.
The 73-year-old man, from Ulm, said he was only testing the bike out but now faces charges of operating a motor vehicle without a licence.
He told officers he meant his creation to be nothing more than a conversation piece.
But police disagreed and told him the 2.3 horsepower petrol motor attached to the bike's rear wheel constituted a motor vehicle.
Police confiscated the bike and sent the man on his way - with a summons and a borrowed bicycle.