I have an 81 and when my bike is cold it runs fine and sounds fine. As soon as the bike is hot it makes a popping or puffing sound. Now it will only do this when I'm letting go of the gas and when stopped at a light.
I think it may be the carb's, and if that aint it what else should be looked at?

Sounds like your mixtures are wrong and it also needs a sync. In short, you need to re-tune your carbs. check the links on the site on how to do that! The tools to do it cost around 50% less than a bike shop to do it for you. Plus when your done, you own the tools and can do it again in the future.

Thanks for the info, I will check that first.

I think Mr. Fork nailed it. Popping like that when backing off the throttle usually means a lean condition. I would colortune the carbs and sync.