Ive been having problems with my 08 TE450. Backfires and flames out. In the summer is would get better as I ride but the last ride was cold all weekend and it seemed to be worse. I decided to check the fuel pump for the fix and found that it was fine and in place where it should be. While clenaing the area under the tank I found the vacuum line from the intake side of the head just hanging there unplugged. On carb bikes Ive worked on, this would go somewhere or get plugged up. Something tells me this should not be open and causing a vacuum leak and should be plugged. Strange thing is, this should cause a lean condition and the plug I took out of it was still a little rich. Any ideas?