Oil Filter Blowout

I changed the oil and filter in my 1978 KZ650.  I also changed the O-ring on the filter cover.  Took the bike to work (about 4 miles) and was on my way home (about 1/2 mile from home) when the filter cover popped out a little bit.  Needless to say, it was pushing the oil out.  I made it home and found oil pouring from the filter cover.  I tried tightening the cover bolt, only to have it pop out.  Ordered a new bolt, and this one seems worse.  Any ideas on a repair?  I greatly appreciate it.

Stripped threads?  I'd say you'll have to drop the oil pan to get a look at the oil pump.

edit: ps: after doing the repair, be sure to use a torque wrench. If you do a helicoil type repair, you may have to modify the torque setting. ???  If the oil filter bolt threads are damaged, you may need to replace it. 

Sounds like you have possibly stripped the threads in the crankcase.
Helicoil type repair would be the way to go without pulling the engine apart.