Rather than start a new thread I will just post here. As many of you know I purchased a second 99 venture to replace the one that was totalled last year and have been struggling with a exhaust popping no matter what tuning I did to the bike. I completely rebuilt the carbs, installed coil over plugs replaced the air filters and spark plugs and checked for exhaust leaks. I even bought a gunson gastester to adjust the carb idle mixture screws with co%. I set all four carbs to 3% and then did a carb sync and the popping was still there. I really didn't want to plug the ais because I believe it does give indication of problems, but as a last resort I went ahead and plugged it. The popping was gone but the bike still had a rich smell. Today I decided to recheck the co% with the ais plugged and sure enough both ais valves were leaking. The front was leaking worse than the rear but both were leaking allowing air into the exhaust continually. With the ais plugged the fronts now registered 10% co and the rears registered 7% co. I retuned the carbs to the 3% co witch required the rears to be turned I over one turn in and the fronts closer to two turns in. I will update performance and fuel mileage when I get a chance to run it because it is currently raining. Just thought I would post this to let everyone know that it is possible for the ais to be bad. The bike only had 47,000 on it when I bought it, so it sat quite a bit before I purchased it and I'm sure that possibly contributed to the ais going bad.
Ron