500cc Class

Mikkola and De Coster dominated the series winning 17 of the 22 races as they competed for the premier division in motocross racing.^[4] Suzuki hired former privateer, Gerrit Wolsink to be De Coster's teammate. Former world champion, Bengt Åberg, left Husqvarna to join the Bultaco factory racing team. Brad Lackey replaced the departed Åberg, joining Mikkola and Arne Kring on the Husqvarna team while, Christer Hammargren replaced Lackey on the Kawasaki team.

The season began at the Austrian Grand Prix where Husqvarna's Mikkola won both races while De Coster's Suzuki had engine problems in the first race then suffered a flat tire in the second moto.^[5] Mikkola continued his winning streak with two more victories at the French Grand Prix, relegating De Coster to second in both races.^[5] Mikkola won a fifth consecutive moto at the Danish Grand Prix while De Coster retired with a loose exhaust pipe.^[5]

De Coster finally scored his first moto win with a second moto victory in Denmark, holding Mikkola to second place.^[4] In the Czechoslovakian Grand Prix, Mikkola took a victory in the first race and, was leading the second race when it began to rain causing him to crash three times, allowing De Coster to take the victory.^[5] At the halfway point of the season, Mikkola and De Coster had accounted for all of the race wins with Mikkola winning 7 motos to De Coster's 3 wins.^[4]

At the German Grand Prix, Mikkola injured his ribs during practice and missed the race, allowing Maico rider, Adolf Weil to finally break the monopoly with a win in the first race at his home Grand Prix while De Coster finished in fourth place.^[5] A malfunctioning front brake caused De Coster to crash in the second race while his Suzuki teammate, Gerrit Wolsink took the win.^[5] Three weeks later at the British Grand Prix, Mikkola was back in action however, a bent brake pedal in a first turn crash forced him out of the race.^[5] De Coster was leading the race when his rear suspension broke and led to his retirement, allowing Yamaha rider Jaak van Velthoven to claim the victory.^[5] De Coster came back to win the second race while Mikkola once again was involved in a first turn crash with Weil putting him in last place.^[5] In a display of determination, Mikkola fought his way through the pack and into third place after 10 laps.^[5]

The series then crossed the Atlantic for the United States Grand Prix with Mikkola holding a 25-point lead in the standings.^[6] De Coster had suffered mechanical breakdowns while leading five races.^[6] In the first moto, Wolsink held the lead before allowing his teammate De Coster to pass him and collect maximum championship points three laps from the finish.^[6] Mikkola rode the last four laps with a flat tire to salvage a fourth-place finish.^[5] De Coster was hindered by a damaged front wheel hub in the second race while his teammate Wolsink barely held off a charging Mikkola to win the race by a one-foot margin and deny Mikkola valuable championship points.^[6] An exhausted Wolsink collapsed from his bike immediately after crossing the finish line.^[6][7]

Citadel of Namur with track visible to far left

Back in Europe for the Dutch Grand Prix, Mikkola and De Coster traded moto wins in the exhausting deep, sand track at Markelo.^[5] Going into the final two events of the season, Mikkola held a 10-point lead meaning that De Coster would have to win three of the last four motos to secure his fourth consecutive 500cc world championship.^[5]

The setting of the Belgian Grand Prix was a rugged, narrow track in the forests surrounding the picturesque hilltop Citadel of Namur.^[5] First held in 1947, the Namur circuit was known as the Monaco of the motocross grand prix circuit in reference to the prestigious Formula One race.^[8]

Wolsink took the lead at the start of the first race while Mikkola and De Coster battled their way to the front of the pack.^[5] When Wolsink's engine seized, the two series points leaders once again found themselves first and second with Mikkola holding on to the lead to the end of the race.^[5] De Coster had to win the final three races to overtake Mikkola for the championship.^[5] Wolsink once again grabbed the early lead in the second race but, soon crashed allowing De Coster into the lead with Mikkola in second place.^[5] De Coster continued to widen his lead to win the second moto to extend the championship points battle to the final race of the season in Luxembourg.^[5] In the first race, De Coster worked his way through the pack to take the lead before his Suzuki suffered an engine problem forcing him out of the race.^[5] Mikkola took over the lead and won the race to clinch his first world championship.^[1]

250cc Class

The 250cc championship was a battle between Soviet KTM rider Gennady Moiseyev and Czech ČZ rider Jaroslav Falta which ended in controversy at the final race of the season.^[2] Moiseyev won the first moto and took the overall victory at the season opening Spanish Grand Prix.^[2] Falta won both races at the Italian Grand Prix followed with a win in the first moto of his home Grand Prix in Czechoslovakia but, then suffered two breakdowns in Poland while Moiseyev won both races.^[2] Falta won a moto in Yugoslavia and at the halfway point of the season, he trailed the Russian rider by 20 points.^[2] Each rider took a second place at the West German Grand Prix but, Falta won a moto at the Dutch Grand Prix to close the points gap to 5 points going into the final race of the season in Switzerland.^[2]

Falta took the lead in the first race and appeared to be heading for victory while Moiseyev was being slowed by a rear suspension failure.^[2] When Falta came upon the slowing Russian rider and tried to pass him, the KTM rider made an attempt to obstruct him allowing second and third place riders, Harry Everts and Håkan Andersson to catch up.^[2] When Falta attempted to pass Moiseyev, the Russian rider collided with him causing him to fall off his bike.^[2] Falta was quickly able to remount but, finished the race in third place.^[2] Falta had to win the final moto to have any chance to claim the world championship.^[2]

As the final race began, Falta once again jumped into the lead while Moiseyev was forced to retire on the seventh lap.^[2] When Falta came upon two Russian riders, Victor Popenko and Eugeny Rybaltchenko, they appeared to attempt to block him.^[2] As Falta tried to pass them, Rybaltchenko rode into him, knocking him down.^[2] He remounted in third place as race officials waved the black flag at the two Russian riders, disqualifying them from the race.^[2] Falta was able to catch up and pass Everts and Gaston Rahier to recapture the lead and win the race, apparently clinching the world championship.^[2] However two hours after the conclusion of the race, jury officials penalized Falta one minute for jumping the start which dropped him to eighth place handing the world championship to Moiseyev.^[2]

500cc

Round	Date	Grand Prix	Location	Race 1 Winner	Race 2 Winner	Overall Winner	Report
1	21 April	Austrian Grand Prix	Sittendorf	Heikki Mikkola	Heikki Mikkola	Heikki Mikkola	Report
2	5 May	French Grand Prix	Gaillefontaine	Heikki Mikkola	Heikki Mikkola	Heikki Mikkola	Report
3	26 May	Italian Grand Prix	Esanatoglia	Heikki Mikkola	Roger De Coster	Heikki Mikkola	Report
4	3 June	Danish Grand Prix	Nissebjerget	Heikki Mikkola	Roger De Coster	Heikki Mikkola	Report
5	9 June	Czechoslovakian Grand Prix	Přerov	Heikki Mikkola	Roger De Coster	Roger De Coster	Report
6	16 June	West German Grand Prix	Beuren	Adolf Weil	Gerrit Wolsink	Adolf Weil	Report
7	7 July	British Grand Prix	Dodington Park	Jaak van Velthoven	Roger De Coster	Jaak van Velthoven	Report
8	14 July	United States Grand Prix	Carlsbad	Roger De Coster	Gerrit Wolsink	Gerrit Wolsink	Report
9	28 July	Dutch Grand Prix	Markelo	Heikki Mikkola	Roger De Coster	Roger De Coster	Report
10	4 August	Belgian Grand Prix	Namur	Heikki Mikkola	Roger De Coster	Roger De Coster	Report
11	11 August	Luxembourg Grand Prix	Ettelbruck	Heikki Mikkola	Bengt Åberg	Jaak van Velthoven	Report

^[4][9]

250cc

Round	Date	Grand Prix	Location	Race 1 Winner	Race 2 Winner	Overall Winner	Report
1	7 April	Spanish Grand Prix	Sabadell	Raymond Boven	Gennady Moiseyev	Gennady Moiseyev	Report
2	21 April	Italian Grand Prix	Gallarate	Jaroslav Falta	Jaroslav Falta	Jaroslav Falta	Report
3	5 May	Czechoslovakian Grand Prix	Holice	Jiry Churavy	Jaroslav Falta	Miroslav Halm	Report
4	12 May	Polish Grand Prix	Szczecin	Gennady Moiseyev	Gennady Moiseyev	Gennady Moiseyev	Report
5	19 May	Yugoslavian Grand Prix	Karlovac	Torleif Hansen	Jaroslav Falta	Torleif Hansen	Report
6	2 June	British Grand Prix	Portsmouth-Charlton	Harry Everts	Torleif Hansen	Torleif Hansen	Report
7	9 June	West German Grand Prix	Bielstein	Gaston Rahier	Joël Robert	Gaston Rahier	Report
8	16 June	Dutch Grand Prix	Valkenswaard	Sylvain Geboers	Jaroslav Falta	Sylvain Geboers	Report
9	4 August	Finnish Grand Prix	Hyvinkää	Harry Everts	Gennady Moiseyev	Harry Everts	Report
10	11 August	Swedish Grand Prix	Upplands Väsby	Torleif Hansen	Gennady Moiseyev	Torleif Hansen	Report
11	25 August	Swiss Grand Prix	Wohlen	Harry Everts	Harry Everts	Harry Everts	Report

^[10]

500cc

Points are awarded to the top 10 classified finishers.

Pos	Rider	Machine	AUT		FRA		ITA		DEN		CZE		GER		GBR		USA		NED		BEL		LUX		Points
1	Heikki Mikkola	Husqvarna	1	1	1	1	1	2	1	2	1		DNS	DNS		3	4	2	1		1	2	1	6	174
2	Roger De Coster	Suzuki		9	2	2		1		1	2	1	3	5		1	1	3	3	1	2	1		2	165
3	Adolf Weil	Maico	2	2		7	3		2	6	3	2	1	2	3		7	6	5			3	3	4	133
4	Gerrit Wolsink	Suzuki	8	5	9	4		4	4	5	4	5	4	1	2		2	1	2	2					124
5	Jaak van Velthoven	Yamaha	10		5	5	5	5	3		10				1	2	3	5	4			4	2	3	109
6	Willy Bauer	Maico / ČZ	3	3	6	6	6		5		6	3	2	3		5		9		7					88
7	Åke Jonsson	Yamaha	5	6	7		2	7	6		5	4	6	4	5	8	9		6	4	3	6	6	5	85
8	Arne Kring	Husqvarna	7	7	3	8			7	3			7		4	4			7	3	4	5		7	80
9	Bengt Åberg	Bultaco	4	4			4	8	8		8		5	6	9	6	8	10						1	69
10	Brad Lackey	Husqvarna			10	9		3		4		8	8	7	7	7	5			5		7	8	9	57
11	Otakar Toman	ČZ	6	8	4		8	6			7														28
12	Arne Lodal	Maico							10	8						10			10	8	5	9			17
13	Victor Popenko	ČZ			8	3			9																15
14	Pierre Karsmakers	Yamaha															6	4							13
15	John Banks	CCM								7				8									5		13
16	Anatoly Botchkov	ČZ				10						6			6										11
17	Christer Hammargren	Kawasaki										10											4		9
18	Raymond Heeren	Maico																					7	8	7
19	Paolo Piron	Husqvarna					7	9																	6
	Serge Bacou	Maico								10			9	10	10								10		6
21	Pauli Piippola	ČZ																		6					5
	Julien de Roover	ČZ																			6				5
23	Jimmy Weinert	Kawasaki															10	7							5
	André Massant	Yamaha																			7	10			5
25	Gilbert de Roover	Husqvarna																		9	8				5
	Andy Roberton	Husqvarna/CCM													8	9									5
	Daniel Péan	Maico																			9	8			5
28	Vic Eastwood	Maico								9			10	9											5
29	Vladimir Khudiakov	ČZ					10													10			9	10	4
30	Jiri Ondryas	ČZ										7													4
	Frans Sigmans	Maico																	8		10				4
32	Zdenek Strnad	ČZ									9	9													4
33	Marty Tripes	Husqvarna																8							3
34	Arne Lindfors	Maico	9	10																					3
35	Jean-Paul Mingels	Bultaco					9																		2
	Toon Karsmakers	Husqvarna																	9						2
37	Ivano Bessone	ČZ						10																	1

Sources:^[1][11]

250cc

Source:^[12]

Points are awarded to the top 10 classified finishers.

Pos	Rider	Machine	ESP		ITA		CZE		POL		YUG		GBR		GER		NED		FIN		SWE		CH		Points
1	Gennady Moiseyev	KTM	4	1		2	6		1	1		2	3	3	2		6	5	10	1	5	1			145
2	Jaroslav Falta	ČZ		3	1	1		1				1	4	7		2		1	2			4	3	8	139
3	Harry Everts	Puch	6	2	3	7		4	4		7		1	4	10	5	3	4	1	4	4		1	1	132
4	Torleif Hansen	Kawasaki					4				1	3	2	1			5				1	3		3	101
5	Gaston Rahier	Suzuki	10			4	8	8	2	2	4		10		1	3	4		9		8	9	5	4	96
6	Håkan Andersson	Yamaha	3	4														6	3	2	2	2	2		81
7	Pavel Rulev	KTM	2	6			3	9	3	10	3	6	6	5								7	6		75
8	Miroslav Halm	ČZ					5	2		3	2	4	8		9	7	10		7		7		7		70
9	Hans Maisch	Maico	9	5	2				6	5	5			2									4	2	69
10	Joël Robert	Suzuki	5	9	4				7				9		4	1					3	8			58
11	Sylvain Geboers	Suzuki		7					5						3	8	1	2					8		53
12	Raymond Boven	Montesa	1			5		7	10					6	5		2								49
13	Torao Suzuki	Yamaha			5											6		3	4	6	6	5			45
14	Jim Pomeroy	Bultaco	7	10			7	3											8	3		6		7	41
15	Vic Allan	Bultaco		8			9	5		4			5			4									33
16	Herbert Schmitz	Puch	8		6	6		6	8					8			9	10	6		10				33
17	Kalevi Vehkonen	Husqvarna								9	9	5			6				5				9	6	28
18	Jiry Churavy	ČZ					1			6										5					26
19	Zdeneck Velky	ČZ			8	3										9							10	5	22
20	Evgeniy Rybalchenko	ČZ			7	8			9		6							8							17
21	Jean-Claude Laquaye	Yamaha			10	10					8	8			7		8								15
22	Antonin Baborowsky	ČZ					2					10													13
23	Jo Lammers	Bultaco								7								7		7					12
24	Olle Pettersson	Kawasaki								8						10	7	9		10					11
25	Håkan Carlqvist	Ossa													8					8		10			7
26	Anatoly Ovchinnikov	ČZ					10				10	7													6
27	Malcolm Davis	Bultaco											7												4
28	Alessandro Gritti	KTM			9	9																			4
	Claude Jobe	Montesa										9		9											4
30	Erkki Sundström	Husqvarna																		9					2
	Uno Palm	Husqvarna																			9				2
	Max Bunter	KTM																						9	2
33	Josef Festa	ČZ						10																	1
	Jean-Claude Nowak	Montesa												10											1
	René Rossy	KTM																						10	1