Semi-successful day today, I centre popped the 7mm clutch spring retaining studs and drilled them out. The one that was rotating was a bit of a swine as I had about 2mm of proud nut to grab hold of with the mole grips, not surprisingly I veered a bit with the drill.
The hub is actually made of steel (although the basket is aluminium) and it appears the posts are swaged in.
I centre popped these and drilled all 5 out. I used a 3mm drill first as I had no idea what size the post had been made at the hub end, I should have guessed that Mr Morini would use a 7mm odd size.
Because 3 of the studs were still in situ I had to use a hand drill and unsurprisingly on two of them, I missed being central on the original holes. Here is the carnage wrought after a couple of hours.
I now had access to the clutch basket which appeared to be retained by an aluminium plate located by 4 socket cap screws. With no clutch plates, no chain attached and nothing to hold onto I could not undo the cap screws as the basket simply rotated on the gearbox shaft as it should do with the clutch disengaged. So I had to knock up a locking device to remove the cap screws.
Not very substantial but it did the job.
Unfortunately with the retaining plate removed the basket would not come off the shaft, it would move about 5mm towards the off position but seemed to be retained by something. Looking carefully I could see no circlips or any other retaining device. After about half an hour of pulling/ judiciously levering, I gave it best.
The last hour was spent cutting up some longish shank 10mm bolts, I will use the shank as the new posts, machine a 7mm stub at one end weld those into the 5 holes in the hub. The other end will be drilled and tapped 5mm to take 5 mm bolts to retain the clutch springs. I much prefer bolts to those horrible shouldered nuts that require a special tool and I chose 5mm because it is good enough for Ducati and to use 6mm would only leave 2mm wall thickness on the posts.
I shall see if the manual I have (more of an owner's manual than a workshop manual) has any hints on how to remove the clutch basket.