You could take it apart and clean it up real good. Take it to a shop and have them take the caliper piston out and hone it and the bore real nice for you. Get new seals and clean the pins up real good and it should work like new. This was done to both the calipers on our 200x and it worked like a charm and was cheap.
Trikes
1984 Honda 200x, 1984 Honda 200m
Bikes
1995 Honda CR125R, 1985 Honda XL100 (gone), 1982 Kawisaki KZ550 LTD,
2001 Yamaha TT-R 125L, 1983 Honda XL185S (current project), 2001 Suzuki SV650S