Harley Evo Rocker Box Install

Mike has front and rear cylinders and heads installed and torqued to factory specs. Next up is to install the front and rear Harley Evo rocker box assemblies as well as pushrods and pushrod tubes. Before installing the pushrod tubes, Mike disassembles the tubes for cleaning and inspection. The inner pushrod tube is cleaned with a Scotch-Brite pad.

The tube is then reassembled along with new pushrod tube O-rings. Mike coats the pushrod tube O-rings with a wipe of clean oil prior to assembly. This aids in assembly and helps the assemblies to seat and position naturally. Mike lubricates the rocker arms and rocker arm shafts. The grooved end of the shafts will face the right side of the motorcycle and align properly with the bolt hole in the lower Harley Evo rocker box when installed correctly.

Mike begins assembly in the rear. The rear Harley Evo rocker box sections are typically more difficult to install due to clearance issues with the motorcycle’s frame. A metal Harley Evo rocker box lower gasket is positioned on the rear head and the lower rocker box is slid into place. Mike demonstrates how to tip the lower section in order to install the rear pushrods and the ⁵⁄₁₆” bolts on the left side.

Evolution push rods are color coded. From left to right (standing/facing the right side of motorcycle):
Purple – Blue – Yellow – Green (Pretty – Bunch – Young – Girls)

If you have pushrods that are not color coded, the two exhaust pushrods are always longer than the intakes. If you find that you have four different length pushrods, they will be, longest to shortest:
Front exhaust – rear exhaust – front intake – rear intake.

With the motorcycle in high gear and spark plugs still removed, Mike turns the motor until the rear cylinder is at top dead-center. This will allow for the least amount of valve spring pressure when tightening the lower Harley Evo rocker box. Lower rocker box hardware is all started by hand and then evenly snugged and torqued to spec. Next, two rubber seals are installed—a large outer and a small center seal.

The middle section is slid into position, followed by another large rubber seal, and finally the top Harley Evo rocker box. The middle and top plates are aligned. Four Allen head screws are installed and torqued to spec.

Mike repeats these steps for the front rocker box assembly.