"He liked to complain about things: people at work, Harry, the council, Harry, the bank, and Harry were just a few of his favourite subjects. This morning, it was motorcycles. "… roaring along like maniacs, the young hoodlums," he said, as a motorcycle overtook them."
Vernon Dursley rants and raves[src]

A motorbike, also known as a motorcycle, is a Muggle device used for transportation, like a bicycle but with a motor, which is nearly always petrol/gasoline-driven.

Sirius Black owned a black motorcycle. He also seemed to show an interest in them, lining the walls of his bedroom with pictures of them. In 1991 Vernon Dursley complained about motorcycles and described the users as 'roaring along like maniacs, the young hoodlums,'.