I used a high temp paint on my bike's pipes at first. It was the dupli-color high temp rated at 500 degrees. That smoked and burned off. I then went to Autozone and bought a can of VHT Fireproof paint. That is rated to 2000 degrees. After sanding the paint off and using a film cleaner that is 48% alcohol to clean the pipes, i sprayed the new paint on. The next day, I started the bike up and let it idle for about 5 minutes. Let it cool and did the same thing again. It did put off a little bit a smoke, not really that much to mention, but it didn't smoke or crack at all after that. Like I said earlier, check to see what the paint is rated at and take your time in cleaning. It will pay off in the end.
Mike