Joined: Nov 2006
Posts: 19,810
Likes: 597
From: NJ, NYC, LI
Bikes: 1940s Fothergill, 1959 Allegro Special, 1963? Claud Butler Olympic Sprint, Lambert 'Clubman', 1974 Fuji "the Ace", 1976 Holdsworth 650b conversion rando bike, 1983 Trek 720 tourer, 1984 Counterpoint Opus II, 1993 Basso Gap, 2010 Downtube 8h, and...
With the one you show, I think what I would do is replicate the decal, or perhaps just parts of it, on laser-printer waterslide paper; and apply the missing parts right over the existing parts. It would not come out perfect, but I could get it looking pretty good while causing absolutely no damage to the existing decal.