dont like the sound of the whining noise you reported, you really should investigate this before any damage is done, is there any lateral play in the magneto rotor? The magnets only just have clearance from the iron cores of the magneto coils, very little clearance! If something isnt right then the magnets can rub against the iron cores and if this is allowed to go on then heat is generated through friction and the coils concered can burn out...I've seen it several times and I hazard a guess that it's down to 'have a go Henry' not torqueing down his rotor nut to the specified torque 40 lbf ft.he got his mate to hold it best he could and just tightened it a bit best he could !
To me this is more important than any other issues at the moment, did you torque it down properly then, with a click stop torque wrench?