Like the title says, has anyone here put an efi rotax 650 from a BMW F650GS into a KTM 640e or a chassis? I have this idea tickling my brain, and wondering if it's been done. I can't seem to search anything on this forum and get anything I'm looking for. My silly brain is thinking that the super reliable and smooth rotax single in the much lighter and more dirtable KTM chassis would be sweeter than the buzzy grenade LC4 (which IS a sweet motor, but they don't seem to last) I love that Rotax designed engine, but Xchallenges are hard to find and expensive, the the new TR650 is way to heavy and poorly suspended. And the F650gs is WAY to heavy and poorly suspended. Is it possible, has it been done? The final drives are on the same side, but I havn't been able to look at both bikes together to see just how it might work.