Will a gsx 1200 bandit fit into a 600 bandit frame?

No, a GSX 1200 Bandit engine will not fit into a 600 Bandit frame without significant modifications. The dimensions, mounting points, and weight distribution of the two engines differ, making a direct swap impractical. Additionally, the 600 frame is designed for a smaller engine, which could lead to structural issues if a larger engine is forced into it. Custom fabrication would be required to make it work, which may not be worth the effort compared to other options.