Chy, I see you tackled this after we talked about it at the rally.
Page 11.11 of the service manual calls for 548 cc or 18.5 ounces for the early model America and Speedmaster.
Here's my set up and my suspension is very good. No dive and no jarring or bounce.
I'm running progressive springs for several years. If I remember the Progressives call for a bit less fluid due to a larger top spacer.
I'm using a 50/50 mixture of 10w and 15w. 532cc or 18 ounces.
Loosen top cap, lift bike and remove the caps, springs, washer and spacers. Lower the bike,Drain fluid ( I use a pneumatic bleeder, sucks it all out)
Add fluid to the correct level.
Additionally I measure with a metal yard stick, the fluid level is 6.5 " from the top of the fork.
Raise the bike, install the springs and spacers. Install the caps. Works every time.
Hope this helps.
