If it is not firing.There is a good possiblitiy you might have to get it rewound or get a ricky stator.They're a little cheaper than stock or look on ebay.
It sounds like the slides start to stick in the carb body when the water splashers on them.Kinda like the carb body starts to sweat from cooling down from the water making the slide stick.
Port it and be done with it!You will see the most noticable difference.If you get a cool head or something done to your head you will have to change the dome in the aftermarket head or get your head rechambered again to your port work.So just port it and do the head the same time and be done with it!
Check the clutch cable to see if it is binding or just slow when returning .If the cable is not returning,it will not have enough slack to release preasure off the ball and rod,but enough to keep the clutch from slipping.