Ironhead Clutch and Primary Chain Adjustment

Kevin is prepared to dive right in and begin a thorough service on his 1977 Ironhead Sportster. Starting off with the Ironhead clutch and primary drive, Kevin begins by inspecting the current clutch lever feel. Kevin determines that the clutch adjustment is currently set too tight. This is likely due to the clutch being incorrectly adjusted in the past. Usually clutch plate wear or clutch cable stretching will cause a lever to become too loose. Ironhead clutch adjustment on this Sportster is very similar to adjusting the clutch of any Evolution or Twin Cam Harley-Davidson.

Always begin by slackening the Ironhead clutch cable until there is excessive lever play. Next, Kevin removes the lower access cover. There is a specialty socket that can be used to spin the access cover off and on. They are available from a variety of manufacturers and are relatively cheap. You can also use the side of a wrench or a brass drift if the cover is frozen or damaged.

Kevin loosens the jam nut with a ¹³⁄₁₆” socket. Now, the adjusting screw is turned inward until resistance is felt. Then, the screw is turned back out ¹⁄₄ to ¹⁄₂ of a turn before re-locking down the jam nut. Finally, the Ironhead clutch cable is adjusted until there is approximately ¹⁄₈” of lever free play.

Next, Kevin moves on to primary drive chain inspection and adjustment. The spark plugs are removed and the rear wheel is raised off of the table lift with a flat jack. The Ironhead Sportster is shifted into high gear so that the motor and drive can be turned. The upper access cover is removed and Kevin feels for the tightest spot of the primary chain. The adjuster is located on the bottom of the outer primary cover. Kevin loosens the jam nut and uses a ¹⁄₄” allen to achieve approximately ⁵⁄₈” chain deflection at the chain’s tightest spot before re-tightening the jam nut.

The primary and transmission compartments will hold approximately 24 oz. of fluid. This Sportster has a weep hole plug, which is really helpful for setting the correct fluid level. Kevin removes the weep hole plug and slowly pours the fluid in through the upper access opening until oil begins to slowly drip from the weep hole. The weep hole plug and access covers are reinstalled and the transmission is set back into neutral.

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