Neil Hudson (Born 24 January 1957) is an English former professional motocross racer.
 He won the 1981 250cc Motocross World Championship.
Ricky Carmichael (born November 27, 1979 in Clearwater, Florida) is a motor racer known for his success in motocross in the early 2000s, having won the AMA Motocross Championship 450cc class seven times and the AMA Supercross Championship 450cc class five times.
 His unrivaled successes in the sport of motocross have given him the nickname "The GOAT"; standing for Greatest of All Time.
The Honda CR125M Elsinore was a motorcycle designed and manufactured by Honda and released in late 1973.
 Modeled after the first Elsinore, the Honda CR250M, the 124cc version sold for $749 at its debut.
 A CR125M ridden by Marty Smith won the 1974 AMA National Motocross championship, echoing the success of Gary Jones on a factory CR250M in 1973 and further spurring the Elsinore's popularity.
 According to the September 1973 issue of "Dirt Bike", the 125 Honda Elsinore was the only off-road bike on the market at the time that offered both speed and reliability.
 Any other 125cc motocross bike at the time would have to have undergone major suspension, motor, and chassis upgrades to be able to handle the rigors of motocross racing.
The 2017 AMA Motocross Championship season is the 45th AMA Motocross National Championship season, the premier motocross series in USA.
 Ken Roczen goes into the season as the defending champion in the 450 class after taking his second national title in 2016.
 In the 250 class Cooper Webb is the defending champion after taking his maiden title last season.
The 2017 British Motocross Championship is the 66th British Motocross Championship season.
 Tommy Searle will start the season as the defending Champion in the MX1 class having taken his first national title in 2016.
 In the MX2 class, Adam Sterry starts the season as defending champion, but he will not compete in the series in 2017.
 For 2017, a new national 2-stroke championship will be contested at four rounds of the championship.
The 2017 European Motocross Championship is the 29th European Motocross Championship season since it was revived in 1988.
 It includes 15 events and 6 different classes.
 It starts at Maggiora in Italy on 16 April, and ending at Villars-sous-Écot in France on 17 September.
 All rounds will act as support classes at the European rounds of the 2017 MXGP.
Jeff Ward (born 22 June 1961) is a British-American former professional motocross racer, auto racing driver and off-road racer.
 He won the AMA Motocross Championship five times and the AMA Supercross Championship twice and the Motocross des Nations seven times.
 After retiring from motorcycle competition, Ward turned to auto racing, finishing in second place at the Indianapolis 500 and winning a race at the Texas Motor Speedway.
 He then competed in off-road truck racing and is currently competing in rallycross racing.
 Ward was inducted into the Motorcycle Hall of Fame in 1999 and, was inducted into the Motorsports Hall of Fame of America on August 12, 2006.
Auguste Mingels (March 24, 1921 – May 20, 1973) was a Belgian professional motocross racer.
 He was a two-time 500cc European Motocross Champion.
 Les Archer, who won the 1956 European motocross championship, considered Mingels to be one of the best European motocross riders of his era.
Cam Jeffrey Emig (born December 1, 1970) is an American former professional motocross racer.
 Born in Kansas City, Kansas, he was one of the premier motocross racers of the 1990s with four major titles for the Yamaha and Kawasaki factory racing teams.
 His main rival was Jeremy McGrath.
 Emig won more motocross races than any other competitor (besides McGrath) in the 1990s with 36 wins and 4 titles.
 He was also the only rider in the 1990s to win back to back 250cc motocross national championships in 1996 and 1997.
 He was a six-time member of the United States Motocross des Nations team, with the U.S. team winning the Championship in 1992, '93, and '96.
 In 1998 he was injured after a five race span in which he won four, and placed second in the other.
 He was often overshadowed by McGrath in the indoor supercross series.
FIM Motocross World Championship is the premier championship of motocross racing, organized by the Fédération Internationale de Motocyclisme (FIM), currently divided into two distinct classes: MX1 and MX2.
 Race duration is 30 minutes plus 2 laps per moto.
 The series runs 18 events with two motos at each round.

Question: Neil Hudson won what premier motocross championship in 1981?
Answer: Motocross World Championship