If you look closely at these pictures you can see that the big twin Knuckle and Panheads were raced as TT bikes and hill climb bikes. Pretty amazing when you consider what they weighed.
I was over at the Garage Company the other day and there were cool bikes everywhere, but the bike that really grabbed me was a beat up old JD Harley Davidson. The old original bikes, especially the race bikes should be restored mechanically and left in their original state of glory. Just my opinion. If they are too pretty to ride they have lost their reason for existing in the first place.