sorry, Barak. I just assumed you might have misinterpreted my answer of removing the Kleen system and confusing it with Natty's post. It
is your choice, if the backfiring doesn't bother you... it just bugged the hell out of me until i found the solution.
my
guess is that the exhaust mixture is lean due to the Kleen system injecting air during off throttle conditions, which leads to the popping.