Technical: Carbs: Model DC
Various Authors

The new Sportster boasted a new carburator- the Linkert Model DC. This carb is quite different than its predecessors. As usual, Harley had quite a time getting things just right, and there were a variety of DC models used through 1965 on the Sportsters, and for one year on the 1966 Shovelhead. There are a lot of DC variations, and quite a few mysteries.

The OSKRG's Identification Guide and What Fits What - Version 1.0 (PDF)

Here's another opinion from Into The Wilderness Trading (PDF)

Quick Reference for Initial Adjustments

When you get your carburator completely out of whack, here's what to do...


Turn both the high- and low-speed needle (1 and 2) all the way in (clockwise). Do not close off either needle too tightly or damage to needle and seat may) result.

Turn low-speed needle (2) (counterclockwise) about 1-1/2 turns. With needle in this position, engine will start, but low-speed mixture will probably be too rich.

Start the engine and after it has reached operating temperature and the choke has been moved to the open position, correct the adjustment of lowspeed needle. Turn low-speed needle (2) in (clockwise) 1/8 turn at a time until mixture becomes so lean that engine misses and is inclined to stop; then, back needle out (counterclockwise) 1/8 turn, or until engine hits regularly with spark advanced and throttle closed and engine running at idle speed. Starting and all around carburetion will be better with lowspeed adjustment slightly rich, rather than too lean.

Adjust throttle lever stop screw (4) as necessary, to make engine idle at proper speed with throttle fully closed. Turn screw clockwise to make engine idle faster and counterclockwise to make engine idle slower. Do not idle an engine at the slowest possible speed because an extremely slow idling adjustment causes hard starting. Changing the idle speed with throttle stop screw is likely to change the low-speed mixture slightly. It will, therefore, be necessary again check and correct low-speed needle adjustment by the same procedure followed in making the initial adjustment.

Check high-speed adjustment, after low-speed adjustments have been completed. Run motorcycle or Servi-Car on the road at various speeds between 20 miles per hour and maximum speed. Have spark fully advanced. Best all-around engine performance can usually be found with the high-speed needle (1) set from 3/4 to 1-1/4 turns open.