Glenn,
Although this might be "not quite right", it's my favorite tip...so here goes again! Under the side cover is a small tube that leads up to a passage through the head. I have found that this tube, with its small ID fittings is prone to plugging.
The rocker assembly should get a ample supply of oil. Although it won't "squirt", it will dribble, (won't we all) and I think some of this should fall down and wash the lifter area.
The fitting that goes from tube/head in the direction of flow toward the rocker assembly can get so plugged it has to be removed and drilled out.
Stuart
