Hopefully the broken bolts come out of the crank case cover with out stripping the threads in the cover. If threads are stripped you may need a new crank case cover, or try putting in some Heli coils. If you need any parts, and get them off line at BPS mention DE10% and you will get a little discount. If new crank case is needed, I would recommend the Bolt hole bushing kit which goes in engine block along with new gasket and oil journal Orings. On the motors we've done, we also replace the block bolts with studs and locking nuts we get locally. They are a metric size 8Mx1.25 grade 8 studs.