Thanks Mr Billy Idle-
Harbor Freight had one for $3.88 - I bought it and I think I hear the noise coming from the chain guides. I'm going to get the guides out and check them , they're only plastic. The Mercedes classic center wants a lot of money for them so I have to be sure.
Stethoscope was a great idea, the rod punched through the brain danger is over rated. You simply pull the rod out and get on with things