has any one seen or heard or have any knowledge of this swap, i have both of these bikes and would love to put this motor in my 300 ex frame, i am a fabricator and have done several swaps but this will be the biggest and i want some tech help before i dive in and i put a 1979 yz400 motor in a blaster frame, i extended the frame 4 inches and fabed up some new mounts and this thing ripped it would spin the rims inside the tires and tear the beads and it did vibrate badly but i put some rubber bushings in the mounts to absorbe some of the vibes but the suzuki lt 500 has alot of vibe to it but is all in using the right size bolts and hard ware( the bolts have to be a tight fit in the mount holes on the frame and motor

 

you would probably have to cut the frame to get the mtor in. the 300ex is a small frame i dont think it will clear for a gas tank. why not a 350x motor with an xr500 head

 

Wasn't it 4 wheel action that put the XR600 engine in a 250x?

Anything is possible!

If you do it, let me know how it comes out!