I have an xs 400 and popped the seat off and noticed the fuse and the far side was all black and had melted the plastic holder around the fuse.  I replaced the fuse about 2 months ago, and I know it is the fuse that the ignition runs through.  so I turned on the ignition and within a few seconds the metal casing for the fuse was hot to the touch.  what does this mean and what is a possible cause????  also if anyone knows what is for sure the proper fuse for that, so I can check to make sure that I got the same one when I replaced it. pretty sure I did but it never hurts to check!!