Grasshopper is the first bike in the game but you can`t unlock this achievement before getting acces to all of the tracks in the game. Once you`ll unlock them all it`s pretty easy just finish all of the tracks from start to the finish.
What I did to make this achievement getting faster was riding all of the tracks but from the last mountain since I forgot until when I was using this bike (once I unlocked another one grasshopper was ditched)
You do not have to ride during night mode. Daytime is enough.