This is the bit of kit I use
I know its ebay UK but I`m sure you can get it elsewhere. Just connected it to the bleed nipple and let it suck the fluid through from the reservoir. Kept topping up the reservoir and now and then stopped the process to pump the clutch. Eventually it sucks through the new fluid with no air in the system.
Not used it on the Harley brakes yet but have used it on all my other bikes and change the fluid every two years. No problems to date or the my Ducati clutch but thats laways a problem with whatever I use.
Am I right in believing the early models did not have a bleed nipple but a bleed screw, which of course would make it more difficult ?