The unfortunate truth is the MK1 brakes were not the greatest! This is why they changed them on the MK2. To do the job right to include the rear caliper as well it gets a little tricky. Just doing the front brakes is pretty much straight forward, just get MK2 forks and switch them over, direct bolt on. Then you can install the 4 piston calipers from a MK2 or better yet, from an R1. You have to change the rotors to MK2 rotors as well. Adding SS lines finishes the job, asnd if you do, get the MK2 set of lines as you will no longer need the short ones for the brake robbing hydraulic anti dive solenoids as the MK2 anti dive is electric. Also with the MK2 lines you will then have the bleeder on the line at the high point near the battery. As mentioned, speed bleeders and a vacuum pump are our friends!!
The last thing to do if you convert is to wire up the anti dive solenoids. Eassy job, get a relay and use the yellow brake line to trigger the primary of the relay to ground. Tie the white wires together to the secondary of the relay and bring 12 volts to the other secondary contact. Ground the black wires from the solenoids and you're done!!!