Removal of Harley Evo Tappet Blocks

The top end components of the Evolution motor generally consist of the rocker boxes, the heads, and the cylinders. Mike has already disassembled this Evo top end. He is preparing to go into the cam compartment, but before doing so, the front and rear Harley Evo tappet blocks must be removed. Both Harley Evo tappet blocks are secured to the right side crankcase with 4 twelve point headed screws. These screws must be removed with a ¹⁄₄“, 12-point socket. It’s best if the socket is ¹⁄₄” drive and the socket must be of good quality. A cheap or old and dull socket will easily strip the head of the screws.

The Harley Evo tappet blocks will typically be somewhat stuck in their position. A firm tap with a plastic, rubber, or rawhide mallet is all that will be needed in order to tap the Harley Evo tappet blocks loose. It is important to avoid letting the lifters drop into the cam compartment cavity when lifting the Harley Evo tappet blocks out of their position.

This is not because the lifters will be difficult to retrieve or because damage will occur, it’s simply because it is important to know the original location and orientation of each lifter. If the lifters are going to be reused, they need to be installed back into their original positions. They also must be oriented so that the bearings will be spinning in the same direction. If the lifters are reinstalled randomly, it may result in premature wear or failure. If the lifters are not going to be reused, it is still important to note their original locations for inspection or possible diagnosis.

JIMS Tools sells a specialty magnet tool that holds both lifters up into the Harley Evo tappet blocks while it is lifted up. If you do not have this tool, you can lift the tappet blocks up and out in one quick motion like Mike demonstrates in this video. Once the Harley Evo tappet blocks are removed, Mike can prepare to disassemble the cam compartment.