easyout?

I think that is a 6mm bolt. It should be a #1 or #2 extractor. Iwould try and drill it with the flutes of the bit packed in grease so you dont drop shavings in the jug. I have also found that a automatic center punch works wonders in pulling broken bolts out. Good luck and let me know how it turns out.
 
i broke the bottom kicker side off once, i believe 2 of the holes go the whole way thru, that one i broke being one of them, i got a dremel in there, cut a slot, and used a stubby straight screwdriver to run it out, pb blaster will be your friend here also, you'll be hard pressed to get any drill in there except a small angle drill, unless you pull the motor
 
Worse comes to worse you can drill it out and retap it for the next size metric and if you do that just do all 4 so you don't have 1 odd size bolt for the intake of course the " safest " method is to use a drill press and a vice that will hold the cylinder straight and not move but yes pb blaster is your friend for sure and good luck with the extraction
 
you have to drill a small hole in the center of the broken bolt then run your drill in reverse with the ez out. try not to damage the threads on the jug though. hope you pulled it out to do this. pretty hard to do in place. (the jug that is) or the whole motor if you don't have extra gaskets