I am not sure whether it hurts the clutch to hold it in going down a grade, and my valk has a lot of resistance that way also. slowing down to put it in neutral is not very handy. leaving it in 5th and just enjoy the ride seems to be the best method. when it comes to mpg on a motorcycle, avoiding jackrabbit starts and riding smooth is probably the best way to go. I find that keeping the valk under 3,ooo rpm nets the best fuel mileage, which is around 60-65 mph. over three grand and those 6 carbs get thirsty.
Jay, I would check your brakes to see if they are dragging if slows downhill in neutral. My vision shift into neutral pretty easily but I usually do it only When I'm coming home from a ride and I shut it off and coast about 300 yards to my driveway.
Mike I doubt holding in the clutch for short periods of time hurts anything. Maybe some additional wear if its held in for extended time.
I've tried EOC in my Harley, but even going down a mountain in Neutral with the clutch in, it seems to lose speed.
Depends on the grade, but it's not unusual at all to lose speed coasting downhill with a motorcycle. They're much lighter than cars but AFAIK they have at least the same aero drag. Checking the brakes is always a good idea, though.