We slapped a 125cc engine on a $100 go kart frame. Entire project came out to $600. Silver engine turned out to be no good so we replaced it with semiauto engine in this video    • 125cc GO KART ENGINE SWAP AND TEST RIDE  
Music used in the video is; Staccato by Vibe Tracks, Shake by Vibe tracks, You like it by Vibe tracks, Invisible by Vibe Tracks. All these songs can be found in free youtube library under video manager in Create section.