HELP! Snapped EXUP bolt

[gixersix]

Sorry, I only seem to be posting problems just lately  :eek

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.

[sadlonelygit]

drilled mine out in situ.
a decent drill bit in a makita cordless and a nice slow speed.

[Falcon 269]

Flatten the busted bolt if necessary and centre punch to ensure the drill starts in central.  But I'm thinking you knew that already ...

Mike

[grim168]

Oh and don't snap an easy out in a drilled bolt because they don't drill out so well. One of the three came out ok one snapped and the top ones going to snap by the feel of it.

[stevierst]

And buy a decent set of drills suitable for very hard metals. Normal hss drills won't touch these studs.

[dazza]

I have always found that using a professional grade cutting compound such as Rocol,  keeps the drill cooler and sharper for longer and really does drill more effectively. Plus,  it smells gorgeous.!

[slappy]

Plus one on the rocol, we use it at work when we cut premium threads, makes a vast difference.

[greg1953]

Three of mine snapped, took it to Armstrongs on Westgate Rd. Newcastle and they did a superb job for around £60.
Greg