There are more than a few 650 in the 400 frame bikes around. The stock motor is pretty detuned. But, you would think that anybody who would do the conversion, would know enough to hop up the engine.

 

It actually sounds like a pretty cool machine if you think about it-- well-mannered 400EX chassis with the stump-pulling torque of the XR650R. I would love to throw a leg over one, I'm curious as how the custom-jobber would compare to the Raptor. How much taller is the 650R engine compare to the 400EX engine? Did they have to do serious chassis mods to slip it in?