What a sweet bike...a real 'gentleman's sporting ride'...after 3 years rebuilding ( not yet finished the tank paintwork) I fired up my 59 A7SS and ventured out after some initial fettling as she ticked over, for a few miles on the local country lanes...first BSA I have rebuilt in like 25 years so I had forgotten as much as I had remembered..and that one was a plunger Gold Flash.
Oh, she is charming.....I've heard it said the 500cc BSA twin pre-unit was perhaps the 'nicest' overall pre-unit twin ever built in British fashion, and I can believe it. Smooth, silent engine (by the standards), love the 4 spring clutch...as tractable and torquey as a 500 single for slow work....dunno about speed as she needs to run in.
Now to track down and eliminate all the small leaks..none at all from the engine I am pleased to say.