Install Variable Length Pushrods In A Harleydavidson Evolution Engine

The pushrods are the long, chrome rods outside the cylinders, framing the air cleaner.

Pushrods are the longest and most visible pieces in a chain of mechanical components that connect a cam shaft inside a Harley-Davidson Evolution engine, with the rockers that open and close the exhaust and intake valves in a Harley cylinder head. The “lift” of these valves determines how much air and exhaust enters and leaves the cylinders. Within this chain of components, pushrods or rockers may be adjusted. It is easier to adjust pushrods than it is to pull apart the top of the engine. Harleys are shipped with non-adjustable pushrods, but the motor company does sell a set of quick install adjustable pushrods that bolt in as follows.


1. Shift the motorcycle into top gear. Raise the bike on a motorcycle jack until the rear wheel is completely off the ground.

2. Cut the stock pushrods in half with a bolt cutter and pull them off the engine.

3. Remove both spark plugs with a spark plug socket and a socket wrench. Shine a flashlight into the front spark plug well and look into it.

4. Slowly turn the rear wheel by hand until the front piston is at the top of its stroke.

5. Replace the O-rings, the lower pushrod covers and the spring cover keeper with new components supplied in the kit by hand using a flathead screwdriver when needed.

6. Loosen the locknut on all of the pushrods with an open end wrench and adjust them to their shortest length.

7. Install the pushrods with pushrod covers by hand, ensuring that the adjuster end of the pushrod is down and the ball end of the adjuster is in the tappet socket. Adjust the pushrods for your motorcycle according to the instructions in the kit.

8. Lower and remove the motorcycle jack. Replace the sparkplugs with a sparkplug socket and socket wrench.