The clutch really needs the correct oil (elf), else it just won't work quite right. It is sensitive to oil and the correct oil makes a world of difference. Mine drug really bad and had rather iffy engagement feel when I got the bike. Put in the elf oil and it doesn't drag at all, feel is awesome etc. The elf stuff is expensive, but it lasts a long time and you only need half a liter at a time anyway so a $40, 2-liter bottle is good for four changes which should be plenty to last a full year or better for most folks.
I would measure the voltage to the fan, bad wiring to the regulator or a bad regulator can sometimes cause voltage to drop off with rpm. I'd also double-check that the connections for ground and power are good for the fan - maybe the vibration from the revs is causing them to not make a good connection. Lewis port have a good reputation, but that'd be a really strange mode of failure for a fan motor.