Well, here we are. A week after putting the caustic soda in I emptied it out as best I could (given all the traps and channels inside an exhaust) and wacked the exhaust on some wood a couple of times, shook it around and wacked some more.
Here is the outcome:
Forgive the image quality- it is poor. and there is water on teh ground too, so the context between carbon and wet concrete may not make the carbon output seem much, plus there is some off camera too.
As you can see- there isn't all that much that came out. I have put the exhaust back on the bike and intend to take a birthday ride to my parents after work, via the motorway to get some heat into the exhaust to get rid of any loose flakes still hanging on, and also get some heat into that exhaust to expell/boil that water out to stop corrosion.
We'll see how well it does- and whether I can get over 70+mph in top! It's a fairly windless day so far so it'll be a good test! I'll then decide whether I should give it another treatment.. or feel happy enough.
EDIT:
I think it was a bit more game to get to 80. I did 75 and feel that it would get to 80. But could hear a ticking. I think this is chain slap however as it is speed related (you can hear it from 65+) as the intensivity increases with speed. The problem with the big 21 tooth front sprocket is the difficulty in achieving a nice medium between proper chain slackness and if wrong a little bit it can probably quite easily hit the lower exit port of the case. There isn't much in it, esspecially with the force of being run I imagine.
Will need to check the tension.
But yes.. It seems like it has more pep at the top end.