I think some folks interpret the technical manual different from others. Section 11.1-3 is relevant to me. I do what I'm confident in and get help with anything else. So, oil, oil filter, spark plugs, brakes and stuff I do but if a head has to come off or the ASI drops dead, it's off to see the wizard. But, I'm always learning, and with a head like a sift, I learn over and over again!!