Dragon Ball: That Time I Got Reincarnated as Yamcha!

DRAGON BALL外伝 転生したらヤムチャだった件

When a typical high school student attempts to sprint down a set of stairs to get a glimpse up a girl's skirt, he slips and hits his head. The boy wakes up to find that he now inhabits the body of Yamcha within the world of the manga Dragon Ball. Quickly recalling Yamcha's multiple deaths throughout the series and his status as a joke in the real world, the student must now utilize his extensive knowledge of the manga to avoid suffering the original Yamcha's unfortunate fate. [Written by MAL Rewrite]