Carlos huertas, when you say you tried Seafoam, ,did you use 1-2 oz. per quart of oil, , , and did you drive it for about 300 miles with the seafoam in? Was the oil a clean "Golden-Amber" color when it was changed?? Some folks have to go more than one oil change before the knock disappears (dont ask how I know this).
Carlos, Don't just order parts until you have checked out a few other possibilities. Folks are recommending you order and change the alternator rubber dampeners. They don't know the history of your bike or if possibly the rubber dampers have already been changed (or not). Unbelievable............!!!