# 1973 AMA Motocross National Championship season

The 1973 AMA Motocross Championship season was the 2nd AMA Motocross National Championship season.

## Summary

The sport of motocross experienced explosive growth in 1973 and motorcycle manufacturers sought to capitalize on the expanding market with all four Japanese manufacturers fielding factory-backed teams alongside their European counterparts. Pierre Karsmakers from the Netherlands dominated the 1973 500cc national championship, winning seven of 12 AMA Nationals and claimed 17 victories in 36 races overall. Karsmakers is credited with helping raise the level of American motocross by stressing the importance of physical fitness and machine preparation. 1973 marked a turning point in American motocross when Jimmy Weinert became the first American rider to defeat the then-dominant European riders in the Trans-AMA Motocross Series at Lake Whitney Ranch in Texas. His victory showed that the level of American motocross had begun to compare with the level of European motocross.
As in the 1973 season, after the season-ending 500cc race on September 9, American riders competing for the AMA national championship continued to accumulate points counting towards the national championship while they competed in the 1973 Trans-AMA motocross series, which began on September 23 and hosted visiting European riders from the Motocross World Championship. Although Karsmakers was a Dutch citizen, he was competing under an AMA license so, he was listed as the "Top American" finisher in the Trans-AMA series.
After winning the 1972 250cc national championship on a Yamaha, Gary Jones was hired by Honda to help develop their new Honda CR250M motocross bike for the 1973 season. He did so successfully to win his second consecutive 250cc national title.

## Nationals
### 500cc

| Round | Date | Location | Winner | Team | Report |
| 1 | March 10 | Daytona International Speedway | Pierre Karsmakers | Yamaha | Report |
| 2 | May 6 | Opelousas, Louisiana | Mike Hartwig | Husqvarna | Report |
| 3 | May 13 | Hialeah, Florida | Pierre Karsmakers | Yamaha | Report |
| 4 | May 20 | Olive Branch, Michigan | Mike Runyard | Suzuki | Report |
| 5 | June 2 | Atlanta, Georgia | Pierre Karsmakers | Yamaha | Report |
| 6 | June 10 | Adelphi, Ohio | Pierre Karsmakers | Yamaha | Report |
| 7 | June 17 | Lake Whitney Ranch, Texas | Brad Lackey | Kawasaki | Report |
| 8 | August 12 | Lake Whitney Ranch, Texas | Pierre Karsmakers | Yamaha | Report |
| 9 | August 18 | Pocono, Pennsylvania | Mike Runyard | Suzuki | Report |
| 10 | August 26 | Sligo, Kentucky | Pierre Karsmakers | Yamaha | Report |
| 11 | September 1 | Alabama International Motor Speedway | Pierre Karsmakers | Yamaha | Report |
| 12 | September 9 | New Orleans, Louisiana | Brad Lackey | Kawasaki | Report |

#### Trans-AMA Series

| Round | Date | Location | Top American | Team | Report |
| 13 | September 23 | Springville, New York | Pierre Karsmakers | Yamaha | Report |
| 14 | September 28 | Philadelphia, Pennsylvania | Pierre Karsmakers | Yamaha | Report |
| 15 | October 7 | Lexington, Ohio | Pierre Karsmakers | Yamaha | Report |
| 16 | October 14 | Washington, Indiana | Jimmy Weinert | Kawasaki | Report |
| 17 | October 21 | Atlanta, Georgia | Pierre Karsmakers | Yamaha | Report |
| 18 | October 28 | Orlando, Florida | Brad Lackey | Kawasaki | Report |
| 19 | November 4 | Houston, Texas | Jimmy Weinert | Kawasaki | Report |
| 20 | November 11 | Phoenix, Arizona | Pierre Karsmakers | Yamaha | Report |
| 21 | November 18 | Puyallup, Washington | Pierre Karsmakers | Yamaha | Report |
| 22 | November 25 | Livermore, California | Rich Thorwaldson | Suzuki | Report |
| 23 | December 2 | Orange, California | Pierre Karsmakers | Yamaha | Report |

### 250cc

| Round | Date | Location | Winner | Team | Report |
| 1 | March 10 | Daytona International Speedway | Bob Grossi | Husqvarna | Report |
| 2 | May 6 | Opelousas, Louisiana | Jimmy Weinert | Kawasaki | Report |
| 3 | May 13 | Hialeah, Florida | Gary Jones | Honda | Report |
| 4 | May 20 | Olive Branch, Michigan | Jimmy Weinert | Kawasaki | Report |
| 5 | June 2 | Atlanta, Georgia | Marty Tripes | Honda | Report |
| 6 | June 10 | Adelphi, Ohio | Gary Jones | Honda | Report |
| 7 | June 17 | Lake Whitney Ranch, Texas | Gary Jones | Honda | Report |
| 8 | July 1 | Tooele, Utah | Pierre Karsmakers | Yamaha | Report |
| 9 | July 6 | Los Angeles Memorial Coliseum | Marty Tripes | Honda | Report |
| 10 | July 15 | Baldwin, Kansas | Pierre Karsmakers | Yamaha | Report |
| 11 | July 22 | Delta, Ohio | John DeSoto | ČZ | Report |
| 12 | July 29 | Unadilla, New York | Pierre Karsmakers | Yamaha | Report |
| 13 | August 12 | Lake Whitney Ranch, Texas | Tim Hart | Yamaha | Report |
| 14 | August 18 | Pocono, Pennsylvania | Rich Thorwaldson | Suzuki | Report |
| 15 | August 26 | Sligo, Kentucky | Gary Jones | Honda | Report |
| 16 | September 1 | Alabama International Motor Speedway | Gary Jones | Honda | Report |
| 17 | September 9 | New Orleans, Louisiana | Gary Jones | Honda | Report |

## Final standings

500cc :
| Pos | Rider | Team | Points |
| 1 | Pierre Karsmakers | Yamaha | 2659 |
| 2 | Mike Runyard | Suzuki | 1427 |
| 3 | Peter Lamppu | Kawasaki | 1126 |
| 4 | Gary Semics | Husqvarna | 1079 |
| 5 | Brad Lackey | Kawasaki | 999 |
| 6 | Tim Hart | Yamaha | 888 |
| 7 | Rich Thorwaldson | Suzuki | 769 |
| 8 | Mike Hartwig | Husqvarna | 756 |
| 9 | Tony DiStefano | ČZ | 566 |
| 10 | Wyman Priddy | Kawasaki | 539 |
250cc :
| Pos | Rider | Team | Points |
| 1 | Gary Jones | Honda | 1445 |
| 2 | Rich Thorwaldson | Suzuki | 1086 |
| 3 | Bob Grossi | Husqvarna | 900 |
| 4 | Jimmy Weinert | Kawasaki | 878 |
| 5 | Tim Hart | Yamaha | 710 |
| 6 | Marty Tripes | Honda | 603 |
| 7 | Pierre Karsmakers | Yamaha | 494 |
| 8 | Gary Chaplin | Maico | 486 |
| 9 | Dewayne Jones | Honda | 485 |
| 10 | Jim Pomeroy | Bultaco | 465 |