The stock silencer on my 300ex has gotten so hot it has burnt my back right fender! There is this black mark and it feels hot! Have any of you guys had this problem and should some heat tape stuff do the trick?

 

Some tape should do the trick, but I think that the problem may be that you are running a little lean. Honda's are jetted on the lean side stock to pass emisions easier, and even a slight reduce in restriction on the intake such as a high flow air-filter, or even just taking the air-box lid off will make it run to a near dangerous heat level. You could either step the needle up, get a bigger main jet, or put the air-box lid back on if you have taken it off. I hope I could be of some help.