It is possible to put a CR 125 engine into a CR80 frame, but it would require significant modification to the frame. The CR80 frame is not designed to handle the power and torque of the CR125 engine, and as such, the frame would need to be reinforced in several areas to ensure it can safely handle the increased stress. Additionally, the mounts for the engine and shock absorber would need to be modified or replaced to accommodate the larger engine. It is also important to note that the suspension and brakes of the CR80 may not be adequate for the increased weight and power of the CR125 engine, and therefore may require upgrading to ensure safe operation.
Overall, while it is possible to mount a CR125 engine into a CR80 frame, it is not a straightforward process and requires a significant amount of modification and fabrication to ensure the safety and performance of the bike.
