My wife has a Suzuki gs500f and it has an ongoing problem and nothing I do seems to change anything. Since the day we bought it, it has two spots on the tac that make a suction sound around the carb area. As you increase the revs, it starts around 1700rpm and then again around 2500rpm. The tack kind of bounces as it spits and pops and once past 2500rpm it seems to run fairly well. I'm not 100% sure its a sucking sound but that's what it sounds like to me. I did a carb cleaning...didn't change a thing. One of the diaphragms was smushed when we got the bike, replaced them with new ones...no improvement. Maybe I'll post a vid later of the tac and the sound. Any ideas? Any help would be greatly appreciated.