Hi, I have a 1950 plunger framed 500 ZB33. Stamped on the crankcase is the following, ZB33A 5785 and it has a frame no- ZB31S.7016. The letter HC is also stamped on the crankcase.
My question is, what does the A stand for and as the engine has a cast alloy head and 1 3/16 Amal 10TT9 carb, was it used for racing or competition? Also were ZB34 cams, barrel head and carb fitted by BSA before exporting to America in 1950. It was sent to R Child Co, Nutley New Jersey USA.
Any information regarding the above would be most interesting to me. the bike is used on dry roads and is a joy to ride.
regards Graham