| | 1998 | Roadracing Grand Nationals |
| | Portland International Raceway | Portland, OR |
| Finish | Driver | Hometown | Kart | Engine |
| | 100cc Controlled Light |
| 1 | | Jeff Boshart | Motive Systems | Parilla |
| 2 | | Chris Hegar | OR | Emmick | Parilla |
| 3 | | Tony Butuso | Emmick | Parilla |
| 4 | | Tim Doll | Motive Systems | PCR |
| 5 | | Blake Schnobelen | CMC | Parilla |
| 6 | | Don Henning |
| 7 | | Jim McFee |
| 8 | | Dal Truby |
| 9 | | Ian Griswold |
| 10 | | Ralph Oakes |
| | 100cc Piston Valve |
| 1 | | Mark Foster | OR | Emmick | Komet K-71 |
| 2 | | Bill Gulick | E.Z.G. | Komet K-71 |
| 3 | | Murphy O'Brien | O'Brien | Komet K-71 |
| 4 | | Ian Griswold | Motive Systems | Komet K-71 |
| 5 | | Dom Cicero |
| 6 | | Mark Revord |
| 7 | | John Musil |
| 8 | | Dennis Lange |
| 9 | | Tim Doll |
| 10 | | Dave Vital |
| | 125-150cc Open/FKE II |
| 1 | | Ryan Hegar | OR | Motive Systems | TM |
| 2 | | Don Bootes | CA | Dominator | Rotax |
| 3 | | Glen Cook | Invader | Rotax |
| 4 | | Bill Busacca |
| 5 | | Craig Hargiss | Norris Kart | Mac Minarelli |
| 6 | | Brad Davis |
| 7 | | Tim Lawrence |
| 8 | | John Jones |
| 9 | | Scott Beaudoin |
| 10 | | John Musil |
| | 125cc Gearbox |
| 1 | | Don Bootes | CA | Dominator | Rotax |
| 2 | | Mark Revord |
| 3 | | Scott Beaudoin |
| 4 | | Dave Hanson | Margay | Honda |
| 5 | | John Musil | Swift | TM |
| 6 | | Chris Knight |
| 7 | | Bill Busacca |
| 8 | | Steve Bower |
| 9 | | Steve Plank |
| | Formula 125 Ltd |
| 1 | | Nick Bruce | Haase | Kawasaki |
| 2 | | Troy Shooter | Tony Esprit | Honda CR125 |
| 3 | | Anthony Williams | MBA | Honda CR125 |
| 4 | | John Ledellaytner |
| 5 | | Chris Knight | Trackmagic | TM |
| 6 | | Gary Glanger |
| 7 | | Brad Davis |
| 8 | | Tracy Warren |
| 9 | | Greg Nutting |
| 10 | | Time Lawrence |
| | IKF Spec Sprint |
| 1 | | Terry Russell | CA | Emmick | Parilla TT-75 |
| 2 | | Joe White | Emmick | Parilla TT-75 |
| 3 | | David Culver |
| 4 | | John Ayeres | Emmick | Parilla TT-75 |
| 5 | | Chris Egger | Energy | Parilla TT-75 |
| 6 | | Eric Ragusin |
| 7 | | Andy Beaudoin |
| 8 | | Lance Margeson |
| 9 | | Al Faas |
| 10 | | Daniel McGregor |
| | Intercontinental E |
| 1 | | Matt Schultz | OR |
| 2 | | Glen Cook | HR Swift | HR Rotax |
| 3 | | David Thomas | Swift | Rotax |
| 4 | | Doug Taylor | HR Swift | HR Rotax |
| 5 | | Terry Reeves |
| 6 | | Steve Taylor | Swift | Rotax |
| 7 | | Chaz Lemmon |
| 8 | | Andy Bailey |
| 9 | | J.R. Osborne |
| 10 | | Richard Whitman |
| | Super Stock Sit-Up |
| 1 | | Terry Russell | CA | Emmick Top | Parilla TT-75 |
| 2 | | Ron White | Sacramento, CA | Emmick | Parilla TT-75 |
| 3 | | John Ayres | Emmick | Parilla TT-75 |
| 4 | | Craig Hargiss | Emmick | PCR |
| 5 | | David Koomjan | CA |
| 6 | | Ian Travagilo |
| 7 | | Al Faas |
| 8 | | Scott Hoadley |
| 9 | | Deborah Harpur | Harbor City, CA |
| 10 | | Dan McGregor |
| 1 | | Doug Cole | PVP Formula E | Rotax |
| 2 | | Dennis Critchley | PVP | Rotax |
| 3 | | Rus Dyer | Invader | Rotax |
| 4 | | Tom Kistler |
| 5 | | Trevor Overington |
| 6 | | Gary Peterson |
| 7 | | Rick Holmboe |
| 8 | | Steve Richarson |
| 9 | | Kyle Rice |
| 10 | | Terry Reeves |
| | Yamaha KT 100S Limited |
| 1 | | David Koomjan | Hi-Rev | Yamaha |
| 2 | | Mike Moya | Yamaha |
| 3 | | Dale Nugent | Yamaha |
| 4 | | Ray Bobo | Terry Ives | Yamaha |
| 5 | | Liz Fisher | Fullerton | Yamaha |
| 6 | | Ron Hines | Yamaha |
| 7 | | Tom Symons | Yamaha |
| 8 | | Larry Dobbs | Yamaha |
| 9 | | Paul Hopkins | Yamaha |
| 10 | | Duane Symons | Yamaha |
| | Yamaha KT 100S Sit-Up |
| 1 | | Ron White | CA | Emmick | Yamaha |
| 2 | | Terry Russell | CA | Emmick | Yamaha |
| 3 | | Bill Madden | CA | Emmick | Yamaha |
| 4 | | Jose Munoz | Yamaha |
| 5 | | Scott Hoadley | Invader | Yamaha |
| 6 | | Mark Steniede | Yamaha |
| 7 | | Dennis Lange | Yamaha |
| 8 | | Dale Nugent | Yamaha |
| 9 | | John Ayers | Yamaha |
| | Yamaha KT100S Heavy |
| 1 | | Bill Gullick | OR | E.Z.G | Yamaha |
| 2 | | Murphy O'Brien | CA | Emmick | Yamaha |
| 3 | | Scott Holmboe | OR | Motive Systems | Yamaha |
| 4 | | Tyler Bureau | Emmick | Yamaha |
| 5 | | Ryan Hegar | OR | Emmick | Yamaha |
| 6 | | Greg Nutting | Yamaha |
| 7 | | Tonly Palazzola | CA | Yamaha |
| 8 | | David Morton | Yamaha |
| 9 | | Joe Lester | Yamaha |
| 10 | | Stan Crocker | Yamaha |
| | Yamaha KT100S Jr. Sit-Up |
| 1 | | Nick Tucker | Mike Wilson | Yamaha |
| 2 | | James Mugge | Fullerton Lion | Yamaha |
| 3 | | Gary Cline | Tony Kart | Yamaha |
| 4 | | Derek Walkoski | Yamaha |
| 5 | | Russell Francis | Yamaha |
| 6 | | Thomas Papp | Yamaha |
| 7 | | Lake Gemmer | Yamaha |
| 8 | | Joe Sullivan | Yamaha |
| 9 | | Noah Harding | Yamaha |
| 10 | | Aaron Sparks | Yamaha |
| | Yamaha KT100S Junior |
| 1 | | Derek Walkoski | Emmick | Yamaha |
| 2 | | Thomas Papp | Margay | Yamaha |
| 3 | | Sterling Robinson | Broken Arrow, OK | Yamaha |
| 4 | | Aaron Sparks | Swiss-Hutless | Yamaha |
| 5 | | Joe Sullivan | Swiss-Hutless | Yamaha |
| 6 | | Ray Kunkle | Yamaha |
| 7 | | Eric Johnson | Yamaha |
| 8 | | Stuart Robinson | Broken Arrow, OK | Yamaha |
| | Yamaha KT100S Light |
| 1 | | Scott Holmboe | OR | Motive Systems | Yamaha |
| 2 | | Bill Gulick | OR | E.Z.G | Yamaha |
| 3 | | Mark Foster | OR | Emmick | Yamaha |
| 4 | | Jeff Boshart | Motive Systems | Yamaha |
| 5 | | Greg Nutting | Emmick | Yamaha |
| 6 | | Chris Hegar | OR | Emmick | Yamaha |
| 7 | | Liz Fisher | Yamaha |
| 8 | | Blake Schnoebelen | Yamaha |
| 9 | | Dennis Lange | Yamaha |
| 10 | | Nick Clemons | Yamaha |
| | Yamaha KT100S Ltd., Heavy Sit-Up |
| 1 | | Jennifer White | CA | Invader | Yamaha |
| 2 | | Larry Dobbs | Track Magic | Yamaha |
| 3 | | Ray Bobo | Terry Ives | Yamaha |
| 4 | | Paul Hopkins | Fullerton | Yamaha |
| 5 | | Tom Symons | Emmick | Yamaha |
| 6 | | Steve McIntosh | Yamaha |
| 7 | | Duane Symons | Yamaha |
| 8 | | Ron Hines | Yamaha |
| 9 | | Stephen Fischer | Yamaha |
| 10 | | Chris Egger | Yamaha |
| | Yamaha Sportsman |
| 1 | | Nick Clemons | Yamaha |
| 2 | | Tyler Bureau | Emmick | Yamaha |
| 3 | | Greg Nutting | Emmick | Yamaha |
| 4 | | Aaron Stanford | WA | Emmick | Yamaha |
| 5 | | Tony Palazzola | CA | Yamaha |
| 6 | | Brad Davis | Yamaha |
| 7 | | Roger Seguine | CA | Yamaha |
| 8 | | Tonly Palazzola | CA | Yamaha |
| 9 | | Brad Davis | Yamaha |
| 10 | | Roger Seguine | CA | Yamaha |