It perfectly normal to have some popping. I've turned my mixture screws out, and shimmed till the plugs were black and it still popped. As of now I have no shims and I had to turn in my mixture screws to just over 2.5 which is still about 1/4 turn outside of stock, I also left the snorkle in, and it runs fine. As long as the plugs are good don't worry too much about the popping. Especially if you have a 2G like mine with the PAIR still on it. In fact after you get outside the "sweet spot" it will actually start to pop some more as there is excess fuel in there to light up. Just do a plug check. If you want to leave the snorkle in there, opening up the mixture screws a bit say 1/4 to half a turn fixes it mostly up untill you get a jet kit.
Think of it this way:
Slight popping/burble plugs have some colour. <----It's fine
Loud popping/gunshot like plugs are white <----- Turn out mixture screws 1/8 turn at a time.