Install Harley Gear Drive Cams

Install Harley Gear Drive Cams

Harley-Davidson Sportster motors use an individual gear-drive cam for each valve. The cams are mounted in series along the right side of the engine under the cam cover. The crankshaft gear engages the cam gears, and each cam gear engages the one adjacent to it. The power flows from the engine crankshaft gear through the cam gears, which rotate the cams and control the valve timing, synchronizing all of the valves with the crankshaft and each other. Once you have removed the old cams from the cam case, the new cams can be installed.


1. Raise the bike with the bike lift. Place the lift towards the rear of the frame so the rear wheel is lifted clear of the ground. Put the transmission in first gear.

2. Remove the flywheel inspection plug with an Allen wrench. Roll the rear wheel until the TDC (Top Dead Center) dimple is visible and centered in the inspection hole. The locater dimple on the crankshaft gear should be at the closest point of its rotation to the gear that it will drive.

3. Insert the cam that is driven directly by the crankshaft gear halfway into its bushing. Rotate the cam until its locater dimple lines up with both the crankshaft dimple and its neighboring cam gears, then push it fully into its bushing and engage the cam gear with the crankshaft gear.

4. Insert the remaining cams into their bushings and line up the locater dimples. Push the cams fully into their bushings and engage the cam gears with their neighbors.

5. Reinstall the flywheel inspection plug.