I just did mine not too long ago, and I tried to keep it simple. I removed the ignition switch and the panel under that switch. I then removed the bolts on top of the forks. Next, I removed the drain screws. (advice: buy a couple of spares, I've done this on two bike now and managed to strip out one of the drain plugs. Don't panic if you do, grab a set of vice grips and turn the drain pug out.) I measured the fluid that came out and it was 10.5 oz each side. I put a funnel in the top of the fork and put back about 2 oz at a time, and bounced the front of the bike a few times to make sure the fluid made it past any air pockets. I replace the existing fluid with Bel Ray 10W fork oil. I've done this at 12900 miles and 15000 miles. I know HD recommends service on the forks at 50000 miles, but, looking at the condition of the existing oil, I would not feel comfortable leaving it in there that long.