Sorry, I only seem to be posting problems just lately
Finally bit the bullet and decided to strip out the EXUP valve for a clean and regrease.
Bearing in mind where the bolts are, soaked them in ACF50, then WD40 and left it 2 days before tackling,
All bolts came out OK, except the bottom-most bolt in the valve end plate. This was tight, so as seen elsewhere, tried tightening it slightly to crack it before loosening. Bolt seemed to move 5 degrees or so, so seemed a good idea. Gradually worked it back and forward those 5 degrees and sure enough - SNAP. Obviously made of cheese.
Anyway, who's got experience, good or bad, on getting these bastards out "in situ" ? I've successfully drilled out snapped off exhaust studs on my GPz before now, so I'm happy to try it without removing the exhaust. What worked for you, and just as important, what didn't??? Thanks in advance.