Can i put a xr650r engine in a 400ex frame?And is it a hard job to install?

 

I am pretty sure it will fit. I believe there was one of these that raced in the desert series. There was also another one claiming there's could do 110 mph at about 50 hp.

 

There are pictures on Off-road.com. Look under the coverage of the Las Vegas 200 and the Vegas to Reno races. The riders actually won the championship for the year beating some big name teams like Alba Yamaha and Duncan/Goldenwest/roll.

 

Well what do i have to do to the frame to put the motor in? And do i need new suspension?