2021 Classes
| CLASS | CLASS NAME | MACHINE REQUIREMENTS | AREA QUALIFIER RACE DAY |
| AMATEUR CLASES: | |||
| 1 | 250 B | 122-250cc | Sunday |
| 2 | 250 B Limited | 122-250cc | Saturday |
| 3 | 250 C | 122-250cc | Sunday |
| 4 | 250 C Limited | 122-250cc | Saturday |
| 5* | 250 C Jr. (12-17) Limited | 122-250cc | Saturday |
| Must be 14 to race 250cc | |||
| 6 | 450 B | 122-Open cc | Sunday |
| 7 | 450 B Limited | 122-Open cc | Saturday |
| 8 | 450 C | 122-Open cc | Sunday |
| 9 | 125 C | 122-125cc | Saturday |
| 10* | 125cc (12-17) B/C | 122-125cc 2-Stroke | Sunday |
| 11* | Schoolboy 1 (12-17) B/C | 86-125cc 2-Stroke/75-150cc 4-Stroke | Saturday |
| Min. Wheels: Front 19"; Rear 16" | |||
| 12* | Schoolboy 2 (12-17) B/C | 122-250cc | Sunday |
| Must be 14 to race 250cc | |||
| VET CLASSES: | |||
| 13 | Open Pro Sport | 122-Open cc | Sunday |
| 14 | 250 Pro Sport | 122-250cc | Saturday |
| 15** | College (18-24) (Sportsman) | 122-Open cc | Sunday |
| 16 | Junior (25+) | 122-Open cc | Sunday |
| 17** | Vet (30+) (Sportsman) | 122-Open cc | Sunday |
| 18** | Senior (40+) (Sportsman) | 122-Open cc | Sunday |
| 19 | Senior (45+) | 122-Open cc | Sunday |
| 20 | Masters (50+) | 122-Open cc | Sunday |
| 21 | Women | 122-250cc | Saturday |
| Must be 14 to race 250cc | |||
| Min. Wheels: Front 21"; Rear 18" | |||
| YOUTH CLASSES: | |||
| 22*** | Mini-E (4-6) Jr. | 1kWh Battery Energy | Saturday |
| 23*** | 51cc (4-6) Shaft Drive Limited | 0-51cc 2-Stroke | Saturday |
| 24*** | 51cc (4-6) Jr. Limited | 0-51cc | Saturday |
| 25 | 51cc (7-8) Sr. Limited | 0-51cc | Saturday |
| 26 | 65cc (7-9) Limited | 59-65cc | Saturday |
| 27 | 65cc (7-9) | 59-65cc | Sunday |
| 28 | 65cc (10-11) Limited | 59-65cc | Saturday |
| 29 | 65cc (10-11) | 59-65cc | Sunday |
| 30 | 85cc (10-12) Limited | 79-85cc | Saturday |
| 31 | 85cc (10-12) | 79-85cc | Sunday |
| 32 | Mini Sr 1 (12-14) | 79-85cc 2-Stroke/75-150cc 4-Stroke | Saturday |
| Max. Wheels: Front 17"; Rear 16" | |||
| Max. Wheelbase: 51" | |||
| 33 | Mini Sr 2 (13-15) | 79-85cc 2-Stroke/75-150cc 4-Stroke | Sunday |
| Max. Wheels: Front 17"; Rear 16" | |||
| Max. Wheelbase: 51" | |||
| 34 | Supermini 1 (12-15) | 79-112cc 2-Stroke/75-150cc 4-Stroke | Saturday |
| Max. Wheels: Front 19"; Rear 16" | |||
| 35 | Supermini 2 (13-16) | 79-112cc 2-Stroke/75-150cc 4-Stroke | Sunday |
| Max. Wheels: Front 19"; Rear 16" | |||
| 36 | Girls (11-16) | 79-112cc 2-Stroke/75-150cc 4-Stroke | Saturday |
| Max. Wheels: Front 19"; Rear 16" | |||
| Must be 12 to ride Supermini | |||
| * Youth age rules apply. | |||
| ** Sportsman: Pro license restrictions apply. See Supplemental Rules for details. | |||
| *** Riders may attempt to qualify in more than one class, but may only enter one class at the National. | |||