The 2012 Grand Prix motorcycle racing season was the 64th F.I.M. Road Racing World Championship season. Casey Stoner started the season as the defending World Champion, while Honda was the defending Manufacturers' Champion.  Moto2 champion Stefan Bradl joined the MotoGP grid with LCR Honda  and 125cc champion Nicolás Terol entered Moto2, racing for Aspar. 
Grand Prix motorcycle racing refers to the premier class of motorcycle road racing events held on road circuits sanctioned by FIM. Independent motorcycle racing events have been held since the start of the twentieth century and large national events were often given the title Grand Prix, The foundation of a recognised international governing body for motorcycle sport, the Fédération Internationale de Motocyclisme in 1949 provided the opportunity to coordinate rules and regulations in order that selected events could count towards official World Championships as FIM Road Racing World Championship Grand Prix. It is the oldest established motorsport world championship.
The Fédération Internationale de Motocyclisme is the global governing/sanctioning body of motorcycle racing. It represents 113 national motorcycle federations that are divided into six regional continental unions.
Road racing is a form of motorsport racing held on a paved road surfaces. The races can be held either on a closed circuit or on a street circuit utilizing temporarily closed public roads. Originally, road races were held almost entirely on public roads however, public safety concerns eventually led to most races being held on purpose built racing circuits.
In the premier MotoGP class, the championship battle revolved around Yamaha rider Jorge Lorenzo and Honda pairing Dani Pedrosa and defending champion Stoner. Lorenzo won four of the first six races to be held in the campaign to open up an advantage over Stoner, before he was taken out of the Dutch TT on the first lap by Álvaro Bautista; Stoner won the race to eradicate the points lead.  In the next race, Stoner crashed out of the German Grand Prix on the final lap and allowed Pedrosa to take his first win of the season.  Stoner struggled in the next few races – despite a victory at the United States Grand Prix  – with his championship challenge ended by a qualifying crash at Indianapolis. After ankle surgery,  he returned to the series and won his final race of his career at his home race, the Australian Grand Prix, for the sixth successive season.  Pedrosa went on a run of five victories in six races, with the streak being interrupted by a first-lap crash at Misano, where he was taken out by Héctor Barberá.  Lorenzo finished second to Pedrosa on each occasion that he had won, and he took advantage of Pedrosa's accident to win at Misano.  Lorenzo ultimately won the title with a second-place finish to Stoner in Australia, after Pedrosa had crashed out of the lead early on.
Yamaha Motor Company Limited is a Japanese manufacturer of motorcycles, marine products such as boats and outboard motors, and other motorized products. The company was established in 1955 upon separation from Yamaha Corporation, and is headquartered in Iwata, Shizuoka, Japan. The company conducts development, production and marketing operations through 109 consolidated subsidiaries as of 2012.
Jorge Lorenzo Guerrero is a professional Spanish Grand Prix motorcycle road racer. He is the 2006 and 2007 250cc World Champion, and the 2010, 2012 and 2015 MotoGP World Champion. He currently competes in the MotoGP class, riding for Honda. He rode for Yamaha from 2008 to 2016. On 6 June 2018 it was announced Lorenzo would be joining the Repsol Honda team for the 2019 and 2020 MotoGP seasons. Apart from his three titles in the premier class, Lorenzo has also finished as runner-up on three occasions. In 2012, Lorenzo became the first Spanish rider to win multiple premier class titles, and with 67 career wins, he is sixth on the all-time wins list.
Honda Motor Company, Ltd. is a Japanese public multinational conglomerate corporation primarily known as a manufacturer of automobiles, aircraft, motorcycles, and power equipment.
In the other classes, Marc Márquez won the Moto2 championship title after a season-long battle with fellow Spanish rider Pol Espargaró; a third-place finish for Márquez at the Australian Grand Prix – despite a win for Espargaró  – was enough to give him his second world title before moving into the premier class for the 2013 season.  He took his last victory in the class at the Valencian Grand Prix, the last event of the season, despite starting from 33rd on the grid. This performance, which included overtaking 20 bikes on the first lap alone, meant the biggest comeback in the sport's history.  Márquez's result was enough to give Suter the constructors' title for the class. The inaugural Moto3 world championship title went to German rider Sandro Cortese, following his fourth victory of the season at the Malaysian Grand Prix,  which gave him an unassailable points lead over his two title rivals Luis Salom and Maverick Viñales in the championship race.  Cortese also became the first rider to win any Grand Prix title for the Austrian manufacturer KTM.  KTM also won the constructors' championship at the Australian Grand Prix, doing so after Cortese won the race.
Marc Márquez Alentà is a Spanish Grand Prix motorcycle road racer and one of the most successful motorcycle racers of all time with seven Grand Prix world championships to his name - five of which are in the premier MotoGP class. Márquez races for Honda's factory team since his MotoGP debut in 2013. He is nicknamed the 'Ant of Cervera' worldwide and 'el tro de Cervera' locally in his hometown, meaning the 'Thunder of Cervera'. He is one of four riders to have won world championship titles in three different categories, after Mike Hailwood, Phil Read and Valentino Rossi. Marquez is often considered one of the greatest innovators of modern MotoGP racing, due to his comparatively exaggerated cornering technique of leaning so far over the bike he seems to be “in constant danger of sliding out”.
Pol Espargaró Villà is a Spanish Grand Prix motorcycle racer who currently rides in the MotoGP class for the KTM factory team. Pol is the younger brother of Aleix Espargaró, and is best known for winning the 2013 Moto2 World Championship. He won the Suzuka 8 Hours in 2015 with Bradley Smith and Katsuyuki Nakasuga, and in 2016 with Nakasuga and Alex Lowes. He is the first rider to finish on the podium rising a KTM motorcycle in MotoGP.
The 2013 Grand Prix motorcycle racing season was the 65th Fédération Internationale de Motocyclisme Road racing World Championship season. Jorge Lorenzo started the season as the defending World Champion, while Honda was the defending Manufacturers' Champion. Moto2 champion Marc Márquez joined the MotoGP grid with Repsol Honda and Moto3 champion Sandro Cortese entered Moto2, with Intact GP.
The MotoGP class saw the introduction of engines with 1,000 cc (61 cu in) in capacity, with a limit of 4 cylinders and a maximum 81 mm (3.2 in) cylinder bore. 
The 2012 season also saw the introduction of four-stroke bikes in the new Moto3 class. 
Claiming Rule Teams
In 2012 the MotoGP class saw the introduction of Claiming Rule Teams (CRT) to allow for participation by independent teams with lower budgets. CRTs were given twelve engines per rider, six more than the other teams and more fuel – 24 litres (5.3 imperial gallons) instead of 21 litres (4.6 imperial gallons) – but were subject to a factory team buying, or "claiming", their engines for €15,000, or €20,000 with the transmission.  The sport's governing body received applications from sixteen new teams looking to join the MotoGP class.