Generator / Rotor Bolts - Sheared and Damaged

[clofan]

Hello everyone! I was glad to find this forum, and hopefully I can get some advice in a dire situation.

A few weeks back my buddy was riding his 2001 GZ250 home, and he heard some metal-on-metal noises coming from the engine, followed by a lockup. I came over and helped him look at it, and we were able to get it push-started after a decent number of attempts. I ran it maybe 150 yards-- it backfired a lot and died when I came to a stop. I thought it was a timing issue. Turns out, I was half right..

There are three bolts holding the generator (edit- These: http://i.imgur.com/JW40nuA.png) onto the roller bearings that touch the crankshaft. As soon as I took off the left side cover, I could see that one of the bolts had sheared off and was stuck in the gap of the large starter idle gear. Turns out, two of them sheared off and were being grinded up and stopping the engine from rotating cleanly.

Without further ado, pictures of the damage:

Back of the generator area. You can see one bolt still standing-- the others are in the bowels of the beast.



What I'm calling the large starter idle gear-- maybe not the correct name, but still. Not a lot of damage here, but you can see bits of bolt (and the bolt itself!) in the bottom of the case.



This is the part I'm most worried about. Actual case damage. Could I patch this with a weld? Any other ideas on how to fix it?



Damage to the interior left side. That lower right hand threaded bolt hole is missing about 1/4 of the walls, where you can see it's chewed up



Finally, the lower half of the two bolts still stuck in the generator outside part. I should be able to drill these out, just need to take it slow.