Ok fella's After doing a lot of research and not finding all the answers in one place, I have compiled everything you need to know for fitting the FCR MX to an XR600. I have all the Part numbers, prices, and pics of the finished install. She runs like a rapped ape now, Hands down best mod I have done to the bike since the rebuild last year. With a little tug on the bars it will wheelie in 3rd with 14-45 gearing. Second gear wheelies come up a little too fast for comfort. Ok on too the Technical stuff. Step 1. Buy a good used FCR MX carb off of Ebay. I got a really clean one from a 2007 CRF250 for $130 shipped Try and find one with the throttle and cables, your XR600 throttle house and cables will not work. Step 2. You need a intake/insulator boot from a XR650L. Can be had on Ebay for about $30 shipped This angles the carb in and down so it clears the frame and the tank. Without it the carb will hit the frame and the tank. XR600 left XR650L right Step 3. Making the connection from the back of the carb to the Airbox. There is a about a 5/16" offset left to right from the carb and your airbox. You can connect this junction several ways. I initially used some plumbing supplies from the hardware store. About $4 in parts. Basically a 1-1/2" PVC coupler and 38mm flexible PVC rubber joiner. Cut to fit and hose clamp it all down. Not the best but the cheapest and most straight Forward. I don't think the NOSS adapter that is sold will work very well here because of the Side to side offset created when using the XR650L boot. The Noss adapter seems to account for a vertical offset.