Sirius Black's motorbike

"A low rumbling sound had broken the silence around them. It grew steadily louder as they looked up and down the street for some sign of a headlight; it swelled to a roar as they both looked up at the sky – and a huge motorcycle fell out of the air…"

- Description of Rubeus Hagrid landing the motorcycle at 4 Privet Drive

Sirius Black's motorbike was a motorcycle owned by Sirius Black. It has a large engine (judging by the noise made and that it can carry a sidecar), but in the book its make is undefined. Book references to "its exhaust pipe" in the definite singular show that, if, as likely, it had more than one cylinder, they all blew into one exhaust pipe, which is likelier for a vee twin then for a parallel twin engine. It has a kickstart. Magic made it much larger than when it was manufactured, emitting a very loud roar. When Hagrid rides it, it is large enough to fit him, a half-giant, and still can carry an ordinary-size person in its sidecar,. Another spell made it able to fly, fast enough to compete with a broomstick.

In the films it is represented by a 1959 Triumph Bonneville T120, ordinary-looking Muggle parallel-twin motorcycle with a sidecar. Deathly Hallows sometimes used a Royal Enfield with a modified side car.

Sirius Black and James Potter (1977)
In 1977 both Sirius Black and his best friend James Potter used the motorcycle while being chased by Muggle policemen for unknown reasons, likely to be speeding. Their chase came to a close when they were cornered in an alleyway by the policemen, but Black and Potter escaped by flying over their heads and away on the motorcycle.

Rubeus Hagrid and Baby Potter (1981)
The motorcycle belonged to Sirius Black, who lent it to Rubeus Hagrid shortly after Lord Voldemort attacked and killed James and Lily Potter and attacked Harry Potter, saying he would not need it anymore. At first, Hagrid found this to be very odd as, according to him, Sirius "loved that motorbike", and before Sirius was shown to be innocent suspected it had something to do with his alleged betrayal of the Potters. Hagrid used the motorcycle to retrieve Harry from the Potter's house and bring him to the Dursleys at 4 Privet Drive, where Albus Dumbledore and Minerva McGonagall were waiting.

Rubeus Hagrid and Harry Potter (1997)
Sixteen years later, when Alastor Moody leads a group of members of the Order of the Phoenix to Harry Potter from the house of his relatives shortly before his seventeenth birthday, Hagrid is chosen to drive Harry and his possessions to the home of Ted Tonks. Arthur Weasley had helped Hagrid modify the bike with various buttons that could shoot out magically-produced traps from its exhaust pipe in case of a chase. This turns out to be useful, as Hagrid uses buttons to produce a large net, a solid brick wall, and dragon's fire, each expanding out of its exhaust pipe, to deter the Death Eaters. However, during the chase, the motorcycle was heavily damaged, made worse when Hagrid tries to use Reparo to fix it, breaking it more. Hagrid has to dive off the motorcycle to keep the Death Eaters from taking Harry, and ultimately they arrive at the Tonks house. Mr. Weasley hides the motorcycle in his backyard shed in hopes of fixing it when Molly Weasley isn't looking.

After the War
After the Second Wizarding War was over Mr. Weasley repaired the motorcycle and later returned it to Harry.

Behind the scenes

 * As in the books Hagrid is twice as tall as a normal man, the motorcycle would have had to be magically enlarged to twice the size each way to fit him: an engine capacity of 649 cc would become a bit over 5 liters, as big as in some trucks.
 * The motorcycle used in the film adaptation of Harry Potter and the Philosopher's Stone was a white 1959 Triumph 650 T 120 Bonneville.
 * The 1959 Triumph 650 T 120 Bonneville is also used to represent the motorcycle in the film adaptations of Harry Potter and the Deathly Hallows but this time it has a blue side car attached.
 * Harry was first brought to the Dursleys' home by Hagrid riding the flying motorcycle, and left Privet Drive permanently 16 years later the same way.
 * The buttons might be a reference to James Bond's gadgets.
 * Harry Potter and the Deathly Hallows mentions "its exhaust pipe" in the definite singular, which shows that, if it had two cylinders as shown in the movie, it had siamese (= 2-into-1) exhaust pipes; the Triumph Bonneville T120 was supplied with two separate exhaust pipes as standard.
 * The Triumph Bonneville was not used in the motorcycle escape scene in Deathly Hallows part one. It was a light blue Royal Enfield. They had originally contacted Royal Enfield looking for a sidecar, but ended up liking the whole rig and used it instead.
 * In LEGO Harry Potter: Years 1-4, Hagrid accidentally crashes the motorcycle into Number 4 Privet Drive's flowerbeds.
 * In the film adaptation of Harry Potter and the Deathly Hallows: Part 1, the motorcycle lands very roughly in part of the marsh at The Burrow, soaking Harry, Hagrid and the cycle itself. Since it was not destroyed, it can be assumed that it was kept by either Hagrid (who had a talent for riding it) or Arthur Weasley.
 * In the video game adaption of the film Harry Potter and the Deathly Hallows: Part 1 instead of being stopped by the various protections around The Burrow, Voldemort is blown away by the dragon fire.

Appearances

 * Harry Potter Prequel
 * Harry Potter and the Philosopher's Stone
 * Harry Potter and the Philosopher's Stone (film)
 * Harry Potter and the Prisoner of Azkaban
 * Harry Potter and the Order of the Phoenix
 * Harry Potter and the Deathly Hallows
 * Harry Potter and the Deathly Hallows: Part 1
 * Harry Potter and the Deathly Hallows: Part 1 (video game)
 * LEGO Harry Potter: Years 1-4
 * LEGO Harry Potter: Years 5-7
 * Harry Potter and the Deathly Hallows: Motorbike Escape
 * Harry Potter Trading Card Game