IH: Carburetor, Intake Manifold & Exhaust Systems - Sub-01B

There were three Bendix carburetors, designated in the parts catalogs, that were installed on Sportsters.

Side by side comparison of 36mm and 38mm Bendix carbs.
Aside from the venturi size, the other main difference that might affect the way it runs is the number of secondary idle discharge ports.
These are the holes that get uncovered by the throttle plate at part throttle settings.
The 38mm has 3 (in addition to the idle adjustment screw hole).
The 36 has 2 (in addition to the idle adjustment screw hole).
The air cleaner screw bosses on the 36mm are smaller.

(Left) 38mm, (Right) 36mm 6)	36mm doesn't have a bowl vent hole here 7)	(L) 38mm has a flat corner, (R) 36mm is round 8)

One feature of an adjustable main jet, (besides the number), is the holes near the bottom that are drilled at about a 45° angle.

Bendix C66-184 adjustable main jet 9)