Tetsu no Don Quixote

For the last three years, the motocross national B-League has been dominated by Kurosu Gen. He has been unmatched in his riding skills and no one was surprised when Gen was promoted to the A-League, the highest league in the nation. But this division has been ruled by an even bigger monster than Gen, the Red Army and its leader Igarashi Shunichi. For the last 5 years, the Red Army has left the competition in the dust and won the championship with ease. Gen is determined to put an end to the Red Army dynasty and take first place but the caliber of motocross riders here are heads and shoulders above what he has seen before.

(Source: MangaHelpers)

Included one-shots:
Volume 1: Mad Fighter
Volume 2: Hokuto no Ken (pilot)