nightride

what kind of paint are you using for your plastic?

I painted all my plastic before i went out riding this last time, it looked great at frist, but by the time i got home a lot of it had chipped away. so before i went out again i put about 4 coats on. it stayed a lot better, but pretty much the same result. is there a paint for plastics that is better than the rest or is there a coat that i should put on before the paint? if you guys have any answers for me then let me know - im lost