update:
I checked the timing table, and something popped out... http://imgur.com/Emq8IJ6
correct me if im wrong, but those 800rpm, 1000rpm and 1350rpm @ 30tpm those 6/3/10 values pop out a bit?
Since, as far as i know 0 means 0 advance, and the bigger the value, the more advanced the timing ? That would explain why i sometimes get popping in the airbox if i pump the gas...