I noticed today there was NO play-slack-clearance at my front brake lever. So I pulled it off & started checking for dirt or corrosion that could be making it that way..... I couldn't find anything wrong, so I decided to file away where the stop 'tab' hit the master cylinder. I stopped when I had just a few thousandths clearance before the lever touching the plunger & went for a ride.
After a few blocks of stops & starts, the squeal- squeak went away.
Another plus is the bike is much easier to roll backwards now. Apparently the contact from the lever was creating drag by not quite releasing the m/c plunger all the way.
I'd be willing to bet this contributes to the relatively short life of front brake pads on these bikes. I would highly recommend checking to see if yours has this same issue.
Hope this helps someone else!!!