I have a 99 Savage that I did the Ryca conversion on.  7200 miles now. Sporty gas tank. Gravity petcock. An open K&N style air filter. And a custom exhaust created by cutting the original at the first horizontal bend and welding a 45 degree slashcut that ends right below the right side cover.  This leaves no other bends in the exhaust other than the original one on the header from the cylinder.  I believe it was jetted when I purchased it as it had a slashcut Jardine exhaust on it. Prior to any mods that I did, it backfired on deceleration.  After modification, it backfired a lot between shifting from 1st to 2nd and even more on deceleration (Understandably).  Very loud.  It also blows a nice blue flame out the exhaust when it backfires as well.  At speed, when I look down at night, a faint small blue flame steadily blows out the exhaust about 2 inches.  (I love the flames but can't help but think its running rich? because of the gravity fed valve which dumps fuel into the carb if not shut off when sitting.  Obviously).  At idle (like when sitting at a light for a long time),  the bike "coughs" every now and again and a little bit of choke takes that right out.  Other than that, the bike ran pretty well for the first 1100 miles that I had it all modded.  Lately, the bike has been suddenly sputtering and almost stalling while I am riding (dangerous... especially when in front of other vehicles going up a hill) and a quick grab of the clutch and rev of the throttle peps it back up.  When I got home I checked out everything to see what I could see and lo and behold, the boot that attaches the carb to the cylinder head has torn and split in half!!!!  

1)My assessment is that the bike has suddenly been stalling because the boot tore bigger and now the bike is getting even more air and less fuel and actually stalling out at speed.  The "coughing" prior during the first 1100 miles was possibly the tear in the boot being big enough to let it gulp air every now and again and almost stalling out.   Replacing this should fix all of those issues.  It needs to be replaced anyways. Thoughts?

2)My second assessment is that with such a direct air flow (assuming there was no tear in the boot in the initial 1100 miles), with the flames, the lack of jetting, I could be ruining my piston and cylinder.  The bike does run hot (normal in an air cooled bike) and has white residue inside of the header close to the cylinder (this was noticed before the bike started cutting out).  Jetting should take care of this all immediately.  I am unsure if I should go up in size or down in size.  I have the jets that Ryca sent with the kit and don't even know what they are.  I can easily figure out how to do it but just don't know if the effort is worth it or what jet I should consider. Thoughts?

3).  Is there a vacuum petcock that will fit the sporty tank that is a 1/2" thread?  (I believe it is that diameter from up here in my bedroom).  That might fix issues as well?

Thanks in advance from a reasonably technically savvy, but lacking the understanding of performance, rider.

PS.  The fuel valve is open completely.  No modifications to the carb have been done.  The vacuum valve has been plugged. Fuel is fresh.  Tank is new with no rust. Tank cap is vented style (this is an issue itself).