Bongo Fury

I noticed the other day that there's some soot about. Might have always been there, not really sure if I'm honest. From the following pics can anyone say if it looks fairly normal or further investigation is required.

I also noticed the No.1 stud head has gone, not sure on any others. No squealing though, is that something that needs doing pronto?

got a snapped stud in pic 2 which will need doing, but if it aint squeking dont worry about it lol they all excrete oily goom esp on turbo outlet, as your crankcase breathes into your air inlet.
Julian

Thanks Julian.