Anybody know something about painting the plastic fenders?  In the future I may want to and was curious how it's done, or any tricks to make the paint stay on  when the plastic bends.

Automotive paint uses adhesion enhancers. I've seen atv fenders painted that don't flake, I was told heating the plastic up before priming helps.

There's a releasing agent in our plastics from the molding process that even the strongest adhesion promoters won't adhere to over a long period of time. There are methods of removing the releasing agent I tried this method in the video but used an oxy acetylene torch and pretty sure I got the plastic to hot. 

The guy says in the comments on that picture rattle can sell not adhere. You have to use an adhesion promoter or primer and a good quality auto body grade paint and spray it on.

sand well ,then fine sand ,clean well, use good ol' krylon plastic paint . about 6 thin coats with wet sanding between each thin coat . did that to mine and 3 years later it was still good . But i stayed with the same yellow color so if it did peel it would be an easy fix . Not sure if i would like to use different color though, but for restoring plastic cheaply it works a treat .

think i used 600 or 800 grit for final couple of coats.  Like i said ,not sure if i would spray yellow plastic black or anything drastic like that .Will look terrible when chipping ,seen some of that on ebay !!