I originally thought you saif YZF, I knew it waws not a YFZ carb, with hot start. A Keihin FCR has the same workings (jets, slide, needles, parts), if its from a GSXR750 rack of 4 or a YFZ450, its inner workings are very similar. TPS, hot start, or chokes might be present, might not, or might be wired differernt (TPS). I know a guy who is running a FCR from a GSXR on his 400ex. That carb is very common on sport bikes and 4 stroke MX bikes, the DRZ has it, the YZF, CRF, KTM's, ect.
You can get it to work jsut fine, however it might take some wiring and plumbing to get her working properly. The FCR MX carbs have a few features fro off raod use, enclosed throttle cable housing, higher capacity float level, ect. Which woudl be a plus over a street bike version, but you could still make it rip.