Thought I'd record the Chase for this bolt segment stuck in the engine case as the Tecno pipe bracket sheared off the lower one.
I purchased these items on fEeBaY. The first is a small set of Left-Handed drill bits with matching screw extractors. I've had very good luck with the bits alone; when they start to bite into the segment, they tend to spin the thing out with no further action required. When I've had to go to Step 2, those screw extractors hardly ever work for me. The other problem I have is that the bolt broke off about 5 or so mm INSIDE the case, so the case threads are liable to be damaged if the drill bit goes off-center.
Enter the larger Kit in the orange plastic box. The little dowels are actually thread protectors that in theory should keep the bit near the canter of the broken bolt while protecting the threads. I figured I'd use the correct-size item WITH a Left-Handed bit, see what happens.
Oh, and I found a 10mm "wobbly" socket to ease the Pain of exhaust header nut removal. We'll see about that, too.
The lower bracket bolt is the one that sheared off. The Tecno pipe bracket doesn't allow both holes to be precisely centered over the case holes, suspected cause for shearing.
Left Handed bits upright, thread protectors and related extractors in the plastic bin.