Either way its gonnaa be time consuming, Ive heard people using Goof Off, I have used Lacquer thinner on a couple bikes, with conditional sucess, the condition being the decals, if they are clear coated it would be fine, if not , they had a tendency to rub off, just dont let the Lacquer thinner soak, and give it breaks , work on different areas, the paint gets soft and its time to let it sit for a couple days.
I did this with a 1999 GT Avalanche

During Paint Removal



After

1988 GT Avalanche

Before Pic



After