How to paint Side panels

I was going to do a matte black or flat black paint job on my 81' KZ1000LTD. I started a few months back but i don't think that two coats of sandable primer is going to cut it:D The tank is chipped and is getting some of that dusty surface rust that i just keep wiping off. I know how to paint the metal parts like the tank and the rear fender but not the plastic side panels. Could i get a recommendation on what grade of sand paper to use when sanding them and maybe a link or something to a step by step list?

Thanks guys,
KT

The one recommendation I've seen is to use some adhesion promoter for the ABS side covers. When I did mine I didn't do them much different than the metal parts, but it hasn't been very long so I don't know how they'll hold up. I haven't noticed any adhesion related issues so far.

I have always sanded the side covers til satisfied with the smoothness (not glass smooth but with enough roughness that the primer will have something to grab on to)and then primer. I then sand the primer to smooth out the surface til I'm satisfied for the final paint coats.I always sand the primer to get out any small imperfections before I put on the final color coats. The quality of the paint job will depend on how you prep before starting to paint and during the different stages up through the color coats. Just remember that that plastic will be soft so don't use too rough of grit and sand lightly. You want to break the glaze and rough up the surface but not to put deep scratches in it. Filler/primer will fill in small scratches to a point but why give yourself more work then necessary? Start with paper on the fine side and if too fine, try a little rougher but don't get too carried away with grit and pressure. I use wet-sand paper to keep sanding grit washed away while you sand.

First off, the problem you are having with the metal pieces is that the paint you are using is from a spray can. The problem with spray cans are they are usually laquer based. these will not give you any corrosion protection and the rust will come back. you need a catalyzed direct to metal primer. If you have any imperfections you need to take care of these first. sand all pieces, even the plasic ones, with 180 grit sand paper. This will allow you to feather out any chips or cracks in the paint. Dont try and use primer to fill any chips etc. Primer will shrink over time and you will see those come right back in a month or so and have to paint the pieces again. After 180 you can prime the pieces. Like I said, use a Direct To Metal Primer, I use a high build sandable version of this and it is great. After letting that dry over night, give the pieces a light dust coat of regular cheap black spray paint. This will allow you to see the areas that still need sanded once you start sanding. The black will stay in the low areas and show you that you need to sand that area some more. You will start with 400 grit, then go back over with 600 grit. Then you are ready for paint. Dont just rattle can the flat black paint on, people will think its primer and you will get asked all the time what color you are gonna paint it. And it wont last since there is no UV protection in rattle can. I suggest SEM brand Hot Rod Black. It comes in a kit with everything you need and looks great! Any more questions feel free to ask. I own a custom paint shop and am happy to help anyone.