You have a UK Cyclone. The C indicates a close ratio box was fitted when it left the factory. Many were cannibalised for parts for proddie racers, so if it doesn't have one at the mo, it's no surprise. I have A50DC 184, AND I'm guessing you have something similar? I believe if you wanted one from new, you had to tell the dealer, who would request one from the factory. In my ownership, my old girl has had all sorts of carburation variations, but apart from that, looks standard. At the mo, she's engineless, waiting for my new 90 deg. job to be finished (See other posts).

You can't make a silk purse from a sow's ear.