Gunner Asch wrote:
Now the big question is how to repair the existing head, reweld the egg
shape and clamp the head an angle plate and rebore it on the mill? Mill
the hole round and make up a steel split bearing to go in the larger
hole and hone it to size? Pin the split bearing in place in the cover
and head? With the appropriate oiler hole? ****..this is getting more
complicated as time goes on.

On the XL185, the end opposite the cam chain runs in a steel bushing
that is pinned to prevent rotation. The 185 head splits horizontally at
the cam centerline. Not sure how your head is configured, this may or
may not be an option for you. It would be the simplest fix, assuming the
cam journal surface is still in good enough shape.
But with that much wear up top and the shade tree idle jet you found, I
think you've got to start wondering how well this bike was maintained
and what other surprises lurk...
I see those XL's show up now and then fairly cheap. I just missed one by
minutes at a yard sale for $100. Buyer had to come back with a truck,
that's why I got to check it out and talk to the seller. It was really
clean, guy said it needed a brand new cylinder sleeve, piston, and bore
job, over $500 worth of parts and work. I would have just set it in the
back yard and waited for a good cylinder to show on ebay. Either cut
your losses now or start looking for a deal on a better one and use this
one for parts. That BMW will be a much better freeway ride anyway....

Jon