Hi, I know this original post is almost two years old, but I was wondering what ever became of this situation? I recently acquired a '77 CB750A and after googling the same issue I let me to your post. Far as I can tell, it's my rear wheel that seems very tight, it will not spin on the center-stand if you try to spin it with your hand. The bike is not in 1st or 2nd gear, and the park brake is 'off' as far as I can tell. I don't hear anything rubbing... did you find out why your's is this way? Thx, Dave-