it could be a lot of things but lets try something simple first. Have you run any injector / fuel system cleaner through your system yet?
I used a little bit of Techron concentrate plus in the gas tank last summer and wow! I couldn't believe how quickly the bike responded to the treatment. It was like getting an immediate tune-up. I actually could feel the difference in the butt dyno. I got it from NAPA for $10, best $ ever spent on a product like that. The PEA(additive) stuff, really works.
http://www.chevron.com/products/ourf...tives/tcp.aspx
Try it, and report back.
The other thing on decel popping is, it can very likely be air leaking into an exhaust joint, either at the exhaust port gasket or at the header to muffler slip-on joint. If you make sure those are sealed, usually the popping goes away.
