@ SSRReally? Ups that´s not good. Hopefully Will has some warranty left. But isn´t it possible to get access to the cams after removing the right casing cover?
Youtube is a hard way to identify sounds but have you checked for an exhaust leak at the head? My nuts have come loose twice. I mean the ones holding the pipe to the head. I would check that gasket before I tear into the engine. I like to start with the cheap fixes first. Try listening through a rubber tube. Sometimes you can locate noises that way. You can try a mechanic's stethoscope for internal noises.