I just bought a KLX300r its an 05. It was running ok around town I took the but plug out and removed the air box cover. It was running a little rough put had a trip planned so i went anyways. It ran ok untill i got to high elevation then it started running really rough heitation would fall on its face when throttled and back fired ocasionally and would die when i stoped. Hard to start sometimes and others it would just fire right up?? Figured this was all to do with the elevation (around 7000 to 8500ft). Well when i got back to town its still running really ruff 2700ft. I noticed a black soot on the fender. I did ride it all that much put could definetly tell there are some issues. Put the butt plug back in and the air box cover back on and took it for a quick ride still runs rough. Anybody got any ideas?? Im thinking about schanging the jetting but the stock 128 you think would be fine at 2700ft. So im not quite sure whats going on. Thank you in advance