Can anyone tell me, (1) Do I need to remove or somehow open the ball/spring valve at the end of the rocker shaft in order to get a thorough cleaning through all the passages (what is that thing for anyway?), and (2) When reinstalling the end caps, I assume the screws go in the holes in the rocker shaft, but the one to the rear (on the opposite end of from the ball/spring) appears to be part of the oil passages, so I wouldn't have thought I'd be putting a screw into that (e.g., the hole on the end where the ball/spring is is a dead-end, in contrast). The service manual isn't much help as the pictures are hard for my old eyes to see well. TIA!