Thanks for the encouraging reply!
This is the first time I have read your explanation anywhere, all the other post I've read say "if the chain is noisy replace it", well I have replaced it and it's still noisy.
Would the mechanic who replaced the chain been able to easily see the rails? As far as I know this motor has never overheated.
How hard is it to inspect the chain again for stretch? I sure don't want to damage this motor which seems near perfect now.