Bo,
I considered repairing the broken tube, with slash cut insert and an upper and lower insert with rosette welds as you have described. But my welder said " I would just replace the tube", so I did. Not really any more work. BTW, the Quaife was only made for the single cylinder BSA for a limited time and is no longer available. I scored mine on eBay from Frank Diehl in North or South Carolina which had only been used in two races, according to seller. However, Nova Transmissions still makes them.
And Dennis,
Gussets are a good idea, especially on tubes subject to moment loads (bending at the weld). This tube doesn't seem to be subject to that, but probably vibrated and fatigue failed due to stress riser at the tabe welded on for the chain guard. And I can flip the shift plate to reverse the pattern. I set up all my race bikes in the reversed or GP shift mode, 1 up, 3 down. I sometimes get confused on my road bikes, some left, some right, and all standard shift.
Bones,
I questioned several experienced minds at Loring about my weaving problem at about 125 mph, including Fred Vance. I was told that fairing equipped bikes can be sensitive to overtight headstock (not a problem on mine) and height. I raised the front end 5mm, and approached the timing lights less aggressively on the next (and record) run and did not get the weave. However, all minds were unanimous in suggesting I get rid of the bias ply rear tire with the radial front. Problem is, 120 width is my limit, and I can't find a 120 width rear radial tire. The solution is to run a front tire on the back, but in the reverse direction. I will do that for BUB. It will also be 70 series instead of 80, so 12mm smaller which lowers the rear. As far as using a belt primary, I've heard that big single cylinders eat belts. Also, the clutch has 25 1/8" diameter rollers which will flat spot pretty easily.