I'll try to stay brief. I have a 89 fxstc with a CV carb (#27492-96)

Got my hands on a CV (274923-96). I used that at my training carb before I rebuilt the one on my bike.

Once I had them both open. I noticed they had different needles. I'm wondering if one is aftermarket or just different stock. Which one should I use. I also have 2 different emulsion tubes. one with a lot of bleed holes and one with maybe 2...

The pics aren't great, the "top" needle is a N72V

 

Bottom needle (with clip) is aftermarket and goes with the emulsion tube with only 2 holes. The aftermarket set up should work best.

 

There’s a more modest taper on the sportster needle, it’s very popular in the Shovelhead world.

 

Like Spanners said, the stock needle has no adjustments per the EPA. That would be the top needle (although the needle could be raised by placing washers under the head).

 

If your using the aftermarket needle (the bottom one) like spanners said, make sure you have the correct emulsion tube for it. The stock emulsion tube (multiple holes) is used with the stock style needles.


It will drive you crazy with carb tuning if they are mismatched. I personally had the aftermarket needle and emulsion tube in my bike when I bought it used (dyno jet), and everything was way rich.


Switched to a CVP 1340 "performance or sportster type" needle and emulsion tube (is like the stock one) and solved my rich issue. YD

 

Look at CV Performance. Put in your set up, order what they recommend. Done. I've done this with 3 different carbs and had NO issues. Or, you can play around with washers and different tubes from now to infinity.