Thanks for the input.I did check the head steady, but not with a wrench, only felt for finger-looseness. I'll put a wrench on it. And still to tighten drive chain. I'm hoping it's something simple like that, and not what cyrusb has suggested....although, I'm thinking he may be correct.I'll keep you posted of my findings.thanks!
Just thinking....IF this was to be the main bearings, is there any reason it would be more prevalent while riding?? As I said, I do not feel any vibration when reving while in neutral. Wouldn't bad bearings present themselves either riding or stationary?