The adjustment **** on top of the carb next to the intake manifold. It rotates 180 degrees... is it an external main jet adjustment?
I got this on EBay with several other items in a 'lot' auction. I don't need it but I'd like to know more about it for a posible re-sale.
The only numbers on it are 27021-71A (on the manifold) and B83B-QC15 (which is a total mystery) above the float bowl on the choke cable side.
I was also wondering... in what year did the single throttle cable get replaced with the double throttle cable?
And did any of the Ironhead Sportsters come with a 42mm carb?

 

Have you checked to see if it comes off a snowmobile?

 

No I haven't, I don't know how to research that so I don't think I will.
The Harley part number on the intake manifold is listed for Shovelheads & Ironheads.
The carb has AMF Harley Davidson cast into the body... I don't know if AMF would've used a Harley carb on a snow mobile. I don't know if AMF even made snow mobiles... I'm thinking this might be a snow job.

 

27021-71A is an intake manifold for L78 to 80 Fl FLH FLH-80 and all L78-80 FX models. Unfortunately I do not have any Sporty manuals or FLT manuals

And yes HD/AMF did at one time make snowmobiles http://www.amfsnowmobiles.com/id25.html

The carb body in general is HD/AMF and could be (or not) for the same above models. FLH has 4 different one listed; FX has 3 for those years. In the parts catalog they list the HD part number for a carb and next to the list they have the word carburetor and another number in parentheses (B28E - fits 81-83 FXS-80, FXB models). There is a different number depending on year, make and model in the 7 listings each with a different number in parentheses. I looked at all carb body numbers from 76 to 84 and there are none listed that have the B83B number next to the carb for FX and FLH models

So I guess the question remains wether it is for a Sporty or an FLT model. Hopefully someone with an early FLT or Sporty can help.

The plastic piece is the cap for the low speed mixture screw.

My manuals show that HD went to dual cables for 1981 models.

Looks like that carb has never been run or even mounted. No grime, grease motor, gas stains or nothing.

 

Looks like the same carb that was on an '82' FLT that I had years ago. I still have the manual if you have any questions I could dig it out.