Broke a cam cap on a 78 kz1000... Now what?

As I was putting my rebuilt head on, I evidently had the left exhaust cam cap crooked somehow as I was tightening it and it cracked in half.. So I understand that these are machined with the head, so they can't be replaced? If I can't replace it can I JB weld it Or do I need to replace the entire head because of one part. I just dumped money into this one and would really just like to replace the broken piece, but I can't find one to replace it with and I don't know if another cap would work on my head.
It seems to me that because the bearings are under each side, that if I JB welded it back together the welded spot wouldn't be under any real stress, each half would handle that individually but that seems pretty hokey. What would you do if it was your engine?

I had this happen to me as well.the owner at our local cycle recycle who seems to really know his stuff told me as long as you keep the bearing that went with the head then you can use another cap.

That would work for me. I was thinking about using new bearings because I would think a different cap would hold it in a slightly different spot, which would mean uneven pressure. I guess it would depend on how similar they were. Does anyone have an extra cam cap to sell?

You are correct, the bore is align bored and the caps are specific to the head and location, with that being said I have seen people change the caps from head to head, but you are taking a chance on bearing wear which in turn will add metal to the rest of the motor

I would take the head off, then to a confident welder who has a TIG welder. Bolt the cap to the head and then weld the crack shut.

You haven't broke the actual cap that holds the shells so you are ok. Just remove and tidy up the broken bridge casting so you end up with two individual caps. Make sure you mark where they go for future reference (front, back/left,right etc). Ideally an extra location dowel in each half would be better but i've done this a few times with no adverse results.

Left side caps provide thrust control on the cams on those engines. I dont' know if I'd trust it to one dowel.

I'd either fix that cap or get one from a junk head and plastigage it. The cam bearings are all the same size so that's got no relative affect on anything.

A little loose on the bearing clearance won't hurt anything. Tight is not good.

check with local kz freak with junk kz heads laying around,dig through his bucket of caps to find one with close clearances when torqued down with cam installed

Hi jumping in on this cam cap.subject , what would people think to me changing from bolt to studs loctited into the head and shallow nyloc holding down the caps I only ask.bevause I have two failed  threads 
reSamantha

The preferred repair is to use heli coil or time serts.  But first, try using a tap to re-do the threads and look for a longer bolt if there are any remaining threads in the bottom of the hole.  The tap should be M6 by 1.25.  A standard bolt is M6 by 45 mm I think.  

Are they not m6 x 1 metric standard? 

A M6 screw/nut has 1,00 mm thread pitch.