Thanks for posting this YZman. It brings back memories of my old 69 BSA. (650 Lightning, bored and stroked to 750)
It was a nice bike, and very fast, but VERY expensive to keep it going (mid 80's and no interwebz).
Lately, I have had thoughts about going back out to AZ and getting it back, since I know the guy I traded it to still has it, but it has been sitting outside for 20 years now, and I could never justify the cost to get it going again.
I wish you the best with it. Enjoy it when you're finished, you deserve it!
Oh, BTW, watch that gas tank. Those old BSA tanks have a way of coming apart at the seam! Going down the road at 80+ with a split tank, getting soaked with gas, and having 50 miles to get home is no fun! I never could get it fixed right, and ended up putting a 3 gallon Kawi tank on it.