Oil Flow Path

[wavelenght]

Hi, Just finished a valve job on my 150 GY6 and cannot see how oil gets to the rocker arms from the crank case.  If someone could help me out with this I would be grateful.  Also, there is a ring on the cam just inside of the cam bearing that is furthest away from the timing sprocket that has a small rectangular projection on it.  This ring will rotate freely in one direction and not the other.  Above this ring on a light gauge bracket is a spring loaded lever or pall.  The projection on the ring stops when it comes against this pall.  If the cam rotates in the reverse direction the projection will lift this pall, pass under, and the pall clicks back down.  Any ideas on what this is or it's purpose?  Thanks.  Happy Hollidays.  Malcolm.