2005 Yamaha 1700 Roadstar was purchased used from dealership. It's previous owner had the carb re-jetted and fitted with Vance& Hines pipes, and a K & N air filter installed. The bike ran great, up until I decided to clean the air filter. Now the bike will run approx 30 seconds to a minute. It sputters and backfires and dies at idle. It also does this around 2000 to 3000 rpm while on a dyno. It sounds like the bike is starving for gas, but the carb has gas in the bowl. All options have been exhausted, all vent lines have been checked there are no obstuctions. The carb has been dipped in a vat of mild acid to clean the jets. Anyone out there with any suggestions or similar situations that have been resolved, please help! I have been without my bike for 3 months and the mechanic has developed a large knot from banging his head against the wall. By the way the mechanic came highly recommended from several sources. He's not some kid from the local dealership. Anyhow please help with some suggestions. Thanks.