Another person contacted me for help a week ago. He has a 2012 bike showing fault codes B86 & B87 and asked if I could fix it. I said that I didn't know as I'd not had a series 2 unit in my hands. He said he'd send it to me to see if I could do some magic with it as there are no used series 2 units on ebay anywhere in the world apparently (series 1 & 3 yes) at present.
The early 4 pipe ones are made by Nissin and have 4 solenoid valves within. The later 5 pipe ones are made by Bosch and have 10 solenoid valves within and more electrical contacts. I did the best I could to clean and flush the internals but I doubt that it's fixed as it has electrical issues, not crud issues like the earlier units. I'll find out when he refits it in a week but l suspect that the last line of the fix will be required.