Adjust The Open Primary Clutch In A Harleydavidson

Adjust the clutch in a Harley open primary when the clutch slips or drags.

Open primary drive systems are a popular and aesthetically pleasing modification available through the aftermarket for older models of Harley-Davidson bikes that are equipped with a dry clutch. The clutch consists of several layers of steel plates and friction plates compressed by clutch springs to transmit engine power to the transmission. Wear of the clutch plates over time causes the clutch to slip and lose power. Adjusting the clutch release mechanism will return the clutch to working order.


1. Remove the clutch cover to expose the clutch release mechanism, if applicable.

2. Loosen the locknut on the clutch cable adjuster sleeve using a pair of wrenches. Collapse the clutch cable adjuster sleeve until the clutch cable is slack.

3. Loosen the clutch adjuster locknut on the clutch pressure plate using a wrench.

4. Hold the clutch adjuster locknut in its loosened position. Back the clutch adjuster screw out using a flathead screwdriver.

5. Tighten the clutch adjuster screw until it makes contact with the clutch pushrod and you feel resistance on the screw. Back the clutch adjuster screw out one-eighth turn.

6. Hold the clutch adjuster screw in position using a flathead screwdriver and tighten the clutch adjuster locknut securely using a wrench.

7. Install the clutch cover, if applicable.

8. Extend the clutch cable adjuster sleeve until there is free play apparent at the clutch hand lever before the clutch starts to release. The amount of free play should be one-quarter inch in 1968 through early 1978 models or one-sixteenth inch in late 1978 and later models.

9. Hold the clutch cable adjuster sleeve in position and tighten the clutch cable adjuster locknut securely.