The decals can be removed with a delicate touch and razor blade. Since yours are cracked it might be easier to use Goo Gone type products to soften the adhesive.
Before I'd remove them I'd place a plastic gridded template over the decal to transfer the size and curvature.
Then I'd go to the local sign shop and have them cut me new decals from vinyl lettering by following the layout on the template.
2013 Voltage 3800, 2012 Chevy 3500 HD
2010 Yamaha V Star 950
2009 Yamaha Raider
Volunteering with Habitat for Humanity Caravanners