Question about mikuni needle jets

I am hoping someone can shed some light on a question I have. I have noticed that some mikuni needle jets are ID'd with an "A” in front of the size indicator - example AO-7 or AO-5 as apposed to O-7 or O-5. Can anyone tell me what the "A" represents? Does it have to do with the size of the jet, or is it related to how accurate the jet will flow, or is it something else entirely? Any information you can provide would be appreciated.

These are the related charts from Mikuni/ Sudco for both the needle and the jet.
www.sudco.com/vol33/56-59.pdf
www.sudco.com/vol33/60.pdf
Hope this helps out.

Thanks for the response Motor, I had seen both of those tables, but they do not appear to indicate what the "A" in AO-7 or AO-5 means. I did not mention in my post that these needle jets are for a kz650 with the vm22ss and vm24ss carbs. If I am correct these carbs use the 258 series needle jets with a bleed type tube.

Unless I am missing something, which is more likely than not, I do not see any reference to the "A". There is information for the 224 series needle jet where some double letters are used to indicate a difference in size increments but nothing about the single letter "A". I am just trying to learn if there is a difference between an AO-7 series 258 needle jet, and a O-7 series 258 needle jet, or between the AO-5 and O-5 jets and if so what the difference is.

I looked quite a bit, all I could find is those AO jets are factory supplied in the carbs and discontinued from Sudco/ Mikuni. I couldn't find any real info on a size difference to just a plain O jet. Maybe someone else can chime in with the Knowledge or send an email to the tech dept at Sudco.

Motor, again thanks for the response. I did send a email to Sudco and if / when I get a response I will post it.

Is it maybe just a batch number (or letter) referance? :huh:

Well Sudco did not know what the "A" means. The individual that responded to my email had never heard of it. I do have to give them credit, in that they did respond very rapidly and did try to answer my question. Too many times I have had companies not respond to my quesions, but then wonder why I do not want to purchase more items from them.

I think it is a Manufactures reference # for the parts going in their carbs. Maybe had a stricter quality control? Seems to be in the Factory carbs but no reference anywhere else. The AO is also on the other carb jets in the parts lists, but maybe not stamped on the jets. Some from an XS Yammy listed the pilots as part #'s including the AO.
??