Ok so i have recently took on a gs project. I have gotten the bike back together and have taken it for acouple little rides(1 mile or so). The bike backfires thru right carb when you get off the gas at say like 4000rpm, and when it sits ideling probly backfires around 4-5 times a minute. I assumed it was a pilot jet issue so i have cleaned the carbs twice paying attention to the pilot jets. But it still does it. Any insight would be great. Thanks

Well, back fires out the carb usually indicate a lean condition. Assuming the carbs are in really good shape (clean with proper jets and floats set correctly) then it could be the valves. What year GS, how many miles, and have you done the valves yet?

Suzi had that problem after she had her 4k mile tune up. Seems the dealer didn't tighten the carb boots enough. I tightened them more and cured her problem.
So what Rich said is what the problem was: she was sucking in extra air and running lean. I think it was more one carb than the other as she would go PUT put PUT put - meaning one side was firing better than the other. After tightening things - she started going Put Put Put Put - and sounding just fine.
So you're probably lean like he said. I'd first check for any air leaks - since you just put everything back together.