How about you master cylinder? U bike is same age as mine, desperately try to find that 3 piston nissin caliber, no luck, so this is what i do to my front brake.
Change the front disk(the stock one is litle bit worn) to new EBC as the brakebads, clean the secondary pistons, and best on the cake, renew the master cylinder parts with Tourmax.
Excellent quality parts with reasonable prise.
The brake improvement is massive, too much to stock springs, so updated to Wirth progressive springs.
Blackbird has spoken...