1988 Suzuki GSX / Katana

Not running. Something wrong with the carbs which I can't figure out. Pulled the plugs to make a compression check and found all four plugs carbon fouled, which I believe means that its running lean. After cleaning the plugs the bike started up but soon died because it was flooding out the air box. I had this problem before until I installed four new float valves and it went away, but now its back. I've had the carbs off and disassembled at least 15 times and am now giving up. The carbs need to be thrown away and known good ones installed. For this reason, its being sold as a parts bike only. I bought the bike as a project bike and had it running well at times but it would always end up with another carb problem. The following items were installed 600 miles ago: Brand new cylinder head and four new pistons and rings. New front and rear sprockets. New chain. New tires. Compression checked with engine cold 8-25-2010 151-156-156-155 Local pick up only.