It is possible to put a 125cc pit bike engine into a 50cc super motard. However, it is not recommended to do this unless you have significant experience with motorcycle mechanics and fabrication. The 125cc engine will likely require modifications to the frame, suspension, and other components of the bike in order to fit and operate properly. Additionally, the bike may become unbalanced or unsafe if it is not properly modified.
If you are considering this project, it is important to do your research and consult with experienced motorcycle mechanics before beginning. You may also want to look into purchasing a complete 125cc super motard rather than trying to convert a 50cc bike.
