More questions from the newbie.. (mudguard went on with some persuasion Pleiades, thanks!)

I'm pretty happy with everything, but am planning to do the TAT with the bike and want to have everything squared away. I'm also having trouble with popping and banging. It did this with the stock exhaust. I've now added an Exan oval classic and the popping is a bit obnoxious, particularly for long distance trail riding. I have made no further mods. Does this means it is running rich? Does this cause long term problems, or just scares yorkshire terriers?

Any ideas and solutions would be appreciated by all!