I have had a long running problem with the front brake caliper not retracting after application. This has always been remedied by removing the caliper piston and cleaning everything. This will last for about a year when it needs to be done agin. I have a 1976 CB550F bought new.
I have asked the dealer mechanics and bike mechanics about this chronic problem and all I ever got was that blank stare like deer in the headlights. The Honda repair manual talks about greasing the back of the pads and the caliper housing but they don't tell you with what and their parts department has never heard of such a grease! I finally got tired of this constant problem and performed a Google search which led me here.
In the brake FAQ section it is said to use Dow Corning High Vacume Silicone Grease ($16.34).
I found also that Permatex has recently offered their Ceramic Extreme Brake Lube (part #24125).
They state that it has a melting point of around 2800 degrees F which exceeds the Dow Corning grease. That should certainly halt migration of the grease. It is available in a blister pack for small quantities or an 8 ounce bottle ($16.94).
I am flabbergasted that the dealers are so clueless, this is a well documented problem here. But I know they are.
While you have been lucky to get some relief in cleaning the caliper, the problem almost always lies with the return hole in the master cyulinder. I would direct your attention to that. remove the lid from the reservoir, pull the lever in slowly and release it slowly. You should see a gurgle of fluid come back into the reservoir indicating that you have pumped some fluid out to engage the brake and some fliuid is returning as you release the lever and the puck should be withdrawing from the disc.
Do a search on master cylinder rebuild and related topics.
These little return holes get plugged with debris from the ages. They can often be cleared with a fine wire like from an electric cord.
Hope that's your problem. When it is, and it is addressed, your brakes will return to acceptable operating condition.
With the lid off the reservoir, the SLOWLY is important as you can pump fluid out onto your tank if you are forceful. Hold a rag around the reservoir while doing it.