Then you didn't ride it.
Paint will NOT stick to plastic under normal riding conditions.
Many have tried it, many thought they knew better. Many were bummed about their crappy looking plastic.
Okie, my experience was all about surface prep, and krylon fusion paint. look at my photo on my profile... yep, that shiny black plastic looks horrible! I also wreck often, and yes, it did scratch, but never chipped.
Wow, that paint looks really good. What was the prep work you did to it? I am going to need some new plastics soon anyways and I might as well see what I can do to them.
Here's my personal experience with paint: I have a 87 Kawasaki X2 (some kind of jetski) and the decals and paint colors were horrible. So I went paint shopping and has mentionned somewhere in the previous posts, I ended up buying some Krylon fusion, but not the rattle can one. The pint one. I preped the surface like I would with a car, primered and painted. So far so good. The only small problem I have encountered is that it will react if gasoline is dropped on it. As far as a fender goes, they tend to wobble and bend much more than a jetski hull..... hummmmmmmmmmm
Just be sure that the climate is good....(med temp, low humidity) clean the plastic really well with an achohol based cleanser, use a plastic specific "prep", allow to dry, and wipe with a terry cloth. Shake the can more than it says to in the instructions. Start shooting the paint before you hit plastic, and dont let off until you've passed the other side. about 2 coats (about 1 hour apart) @ 6 inches works good. Good luck.