Need some advice with a problem on my XR with a Sudco FCR41mm carb. I am on a 6 month trip on my XR650L through central and south america. I bought a FCR from Sudco which was supposed to be pre jetted... Came too lean, ended up making a few changes. It runs well at all throttle positions at sea level up to about 5000'. Everything runs and feels right except when I am riding in traffic or some slow off road riding it just dies. It only dies when I have the clutch in and am rolling to a stop or slowing down for a turn or something. It fires right back up no problem though. Also, i was told it blows some black smoke when I fire it back up after it dies. I'm at a complete loss right now... So far I've done the following: -Tried it with varying fuel screw settings and does it on all of them. -Raised the idle, which may have made it worse. -Pulled the top and and bottom end of the carb apart and sprayed it with Carb cleaner. There was a chunk of dirt on one of the floats which i clean off. Still dies exactly the same way. -Switched out the spark plug which ended up helping it but it still happened just with less frequency. I'm going down the road that I've got some kind of ignition problem. But this definitely started happening after I installed the carb and progressively has gotten worse. Any help would be appreciated! Thanks.