downshift and excessive backfiring 2nd gen

[Mobile]

Hi, I am having excessive backfiring when I downshift, checked carb sync, ok checked hoses to erg and looked for leaks on exhaust and intake manifolds, bike runs great, idels good starts good, I've had bike since new, 105895km on the bike regular service, there where plugs on the egr but we removed them, and it still backfires, so I would like some response to my problem and Im sure someone can give me the answer, thanks for the help to come, I will look foreward to your replys, this has come on over the past few weeks, Thank You .." Mobile " ps: the plug removed from the front hose had a black layer of carbon on the top of it, and I wonder if that would indicate the erg is defective ?

[edger]

How are your pipes? Are they shot? I don't know about the ventures but on my last bike it backfired something fierce until I replaced the baffles in the pipes. That cured her. Guess not enough back pressure from the pipes can cause it as well.