Motorcycle Repair: *Fire in the hole* problems!, plug gap, drag pipes

Question
I have a 2001 Indian Chief w/ an 88 cubic inch S&S. The coil is stock as far as I know.  I have consistently had trouble with with plugs fouling. I bought the bike as a second owner.  The original owner put on drag pipes and a DaVinci carb kit on the bike.  When I was originally having trouble fouling plugs, I took it in to the shop to have them look at it.  After replacing the voltage regulator and leaning the carb out I still have the problem however not as severe.  If I put a new set of plugs in and run 50 miles around town and pull them out, they are black. I can wipe the carbon off. The plug is dry. I have recently had problems with it backfiring and sluggish throttle response. Now when it idles it is definitely lacking power, if I blip the throttle it stutters then backfires. My oil smells a little like gasoline. I am not sure where to take it from here. Could I try a hotter plug?  If so how hot? Right now I am running Autolite 4265's gapped a .041". I live at about 6500feet. I don't seem to have as much trouble with it when I have the throttle open on the highway. But stop and go in town it seems to load up. The plugs will foul out if I let it idle for over a couple of minutes. Do you think it may be the coil, or should I try a different plug?  If you can help at all, any info would be greatly appreciated!

THANKS,

Ramsey

Answer
There are a few different reasons for fouling plugs. One is the coil is not hot enought, so I would do a OHMs test ont he coil. Next is plug wires, so do a OHMs test on them. the other is the carb not jetted right. If you have to big of jets then it will fould plugs. Your plug gap should be .040, not .041
Good luck and happy riding
Mike