I painted my bmx, stripped it to bare metal with nitromors, 4 good coats of primer (from an aerosol can) wetsanded, 2-3 coats of topcoat and 3 coats of laquer, it came out fine with no dirt in it, but did get a couple of runs though where it was abit thick. It's pretty tough considering the abuse it gets!!
One thing worth noting is that aerosol laquer takes aaaaaages to fully harden, unless you have a uv lamp, so would give it 2-3 days before handling and fitting it up again
Stu