I am remodeling the whole kitchen. Sink and all. I took out most of the 1 1/2 galvanized pipe and put in a garbage disposal which has a 1 1/2 inch pipe and put it to a 2 inch pipe which runs down to a 1 1/2 inch pipe then to a 2 inch pipe. This 1 1/2 inch pipe is approx 3 feet before it hits the 2 inch pipe and out to the main drain.

Since everything is new, I would not expect any burping sound but once the water drains, it wait a few seconds and you hear it burping.

Could the problem be going from a 1 1/2 inch pipe to a 2 inch pipe back to a 1 1/2 inch pipe to a 2 inch pipe?

Or could the vent pipe be clogged?

Thanks - JZ

Sounds like the vent pipe is partially clogged you need to snae it from the roof vent and add 16' more when it hit the grond, Good Luck.

John