Derbi DirtBoy 10 ( 10 inch wheels ) as opposed to the DirtKid 12 ( 12 inch wheels ) . 49cc - 8hp - 8650rpm - Direct drive - 4 stroke -Seat height around 2 foot - cost new 2020 euros - cost to me £41 off ebay . Shown with mockup of CRF50 plastics . From what i can gather -Derbi is owned by Piaggio Aprilia and some how use the Malaguti LEM50 frame ? and fit their own engine .or the other way around maybe ?? Sound amazing for a little 50 - cross between a 125 4 stroke and a KX125 . She needs a lot of work - Re Chromeing - new tyres - new cables - frame re painting - new sprockets & chain - new bars and controls , but well worth it just to hear the engine rev . I will add photo's as the work progresses .