Will a yz450f motor fit yz125 frame?

It is possible to fit a YZ450F engine into a YZ125 frame, but it would require extensive modifications. The YZ450F engine is significantly larger and more powerful than the YZ125 engine, so the frame would need to be reinforced to handle the additional stress. The engine mounts, exhaust system, and other components would also need to be modified to fit the YZ125 frame.

Here are some of the specific modifications that would be required:

* The frame would need to be reinforced in several areas, including the head tube, swingarm pivot, and shock mounts.

* The engine mounts would need to be modified to fit the YZ450F engine.

* The exhaust system would need to be custom-fabricated to fit the YZ125 frame.

* The air intake system would need to be modified to fit the YZ125 frame.

* The electrical system would need to be modified to accommodate the YZ450F engine.

It is important to note that this type of modification is not for the faint of heart. It would require a high level of skill and experience in motorcycle mechanics. If you are not confident in your ability to perform these modifications, it is best to consult with a professional.