first of all a 6mm drill bit must be able to slide under the carb slide/ OK!
your ignition - if backfiring - is probably trying to start the bike which is good news.
the stator wants to be set 2/3rds ******** on the only '98 i recall working on. I have a video on my facebook page about timing a '98 501.
you then need a wet plug and then you need to keep drying it with a rag and air etc. don't use the choke for more than one kick in 5,6,7,8 kicks.
if the plug was REALLY wet it has had it. suggest a new one, start the bike and when fully warm you can pop it in and let it burn everything off....all on another day.
regards
taffy