Thanks for all the great feedback!
...Only thing not on your list was clean and grease the swinging pivot pin
Yes, good point, I forgot to mention that I also disassembled the pivot, greased it, and made sure is swivels freely.
...caliper housing impeccably clean is a must, especially in the seal groove is very important
...If your piston has pitting, than it may never work smoothly. Be sure to replace the seal ring.
I didn't mention in my first post that I actually did this twice, the first time with a NOS piston and the second time (with the parts bike caliper) using a SS piston I bought on Ebay (both times with a new seal ring) - so both times the piston was in perfect shape - same "drag" results both times.
Regarding the seal groove - I'm starting to wonder if I cleaned it well enough... or, conversely, if the groove was damaged by over cleaning (between myself and/or PO's) I noticed on parts bike caliper there seemed to be some scratches in the grove.
... Slight contact is normal, and unavoidable, in any caliper system but pressure that creates heat is not. I would suggest riding with some heavy braking stops followed by some light braking and cruising brakes off. This will "set" your operating alignment and then check for drag.
...What I have noticed is that its improved markedly in feel and stopping power with use; an hour of hard riding and braking seemed to do the brake wonders.
I'm hoping this may be the case (just need to use it for a while for everything to set)... but my gut tells me this probably isn't it, as it didn't seem to work the first time I rebuilt the caliper.... I'll ride it for a few hundred miles and see if anything improves.
When I check my wheels I push in the pads and spin. I get the same amount of turns as you. I adjust the pad screw, and then I use small pumps at the brake lever. I found on newer bikes if I pump with one pump the wheel drags. I think it is because the oring is over extended and can not retract the the pad. I have no idea if it works better on old Hondas but it works for me. Urban legend? If that doesnot help, the oring may need to be replaced and the oring groove cleaned as other posters suggest.
Steve
I've also wondered about this - which would mean the adjustment of the fixed pad is critical. Intuitively this makes since - if the distance the piston has to travel is within the range the seal can distort before it slips (maintains static friction vs. kinetic friction) it would have more "grab" on the piston and maintain it's distortion. Of course, at some point the piston does have to "slip" to make up for the reduced pad thickness as it wears - maybe the heat/vibration of use re-sets everything after a "slip"
However, I've played with the adjustment forever, trying different distances, and also did like you said using small pumps to slowly move the piston in. - still the same results
The one other thing I didn't mention is a possible issue with the disc. I notice that when I adjust the fixed pad just right (or as close as possible without touching), the disc slightly makes contact "scrapes" at the same point during every revolution. I had the wheel trued and ask the shop to measure the run-out on the disc. They told me the disc was withing spec. Unfortunately, I don't have much confidence in the shop (and I made the mistake of telling them the run-out specs when I dropped it off)... I never got them to tell me the run-out measurement... just said it was within spec. They also put the tire on in the wrong direction
However, I don't think that's the issue either, as I still get the same revolutions when I swap out the front wheel from the parts bike (and it doesn't have the "scrapping" problem)
Maybe I'll try a third rebuild from the caliper off my other "parts bike".. which are really my other project bikes that are slowly turning into parts bikes.
