I used a larger rotor from a YZ250F, had a machinist cut out the center of the stock TTR and YZ rotors, then weld the stock center to the YZ outer, thus creating a larger brake rotor. He then fabricated an adaptor plate to move the caliper out for the larger rotor. I used a YZ caliper just because I had a spare, you could use the stock one also. With a steel braided cable also, I have monster brakes !!!