Randy,

I've done this a couple of times and have had no issues with it. Back when I was running OSs, I sold a 1.40 RX EFI to Blaire Page and converted it over for him and he flew it a bunch with no issues, and when I had some bearings go bad in a 1.40 RX and didn't have any spare bearings, so I converted a new EFI over to an RX and flew it for a while with no issues. Two strokes are pretty simple.