im not sure what you guys do here, but ive never been a fan of painting plastics per say plastics on the exterior of a car or a quad. a part that will flex, the paint will crack.
im more of a fan of just buying new plastics. albiet it will cost a bit more, but it will look better longer.
if you do insist on painting your plastics look into plasti dip. its a soft paint that will not crack, but also can be pealed off at any point back to the factory finish/paint.
stratton.