Not much info out there on replacing this seal. I have a pretty good little oil leak that I thought was coming from the upper cyclinder and pooling around the plug but after further inspection, it is coming out of the tach cable intake, esecially when warm and revved. After I little diagnosis from the great Ben Miranda, I have a tach seal on the way. Upon getting the stubborn screw above the tach cable off with an impact driver, I realized it looks like I will have to unscrew the top end of the engine meaning I will have to mess with the valves. Is this the only way to get to this seal? I have not tampered with the valves before so I don't want to screw them up. I will have to set them after. I know needle nose pliers should do the trick when I get to the seal but is there anything a novice mechanic like myself should know about this operation? Thanks in advance.