I had a front brake binding on my '90 VFR project, cleaned, inspected, lubed, reinstalled... the pads still bind. So, I removed the really sticky pistons and seals, ruining one piston in the process. No worries, just give a call to my local aftermarket shop -- oops, no piston/seal kits available? What? I've rebuilt second generation calipers in the past so I assumed that kits would be available for the newer models too.
So, anyone know of a source? I see ebay has a seller in England with kits but a disclaimer that they may fit other market bikes, but he only warrants that they will fit the UK models. Anyone?
The caliper piston seals should be common to a shit ton of Hondas. I know the rear ones in my 800 fit XR's and the like.
Get on Ronayers.com. check the part numbers and plug them into the "where does this part fit" and you will probably come up with a bunch of listings, so if they fit a wide array of Hondas that are newer than your '90, you should stand a good chance of having them available still.
not sure if you found seals yet but I just completely rebuild both front calipers with parts from Ronayers.com. All of the piston seals and even the little rubber boots that the calipers slide on were available. Throw in some M8 x 1.25 by 24mm speed bleeders and you're golden! Funny, now that I've rebuilt the calipers, forks, and put on steel braided lines, I've decided to go CBR 954 front end on my 93. can't wait!