Do I uprate master cylinder??

[C.A.R.]

The braking force is effectively still better as Darren points out this is not 'brake fade' so to speak, it's just that you are literally trying to operate bigger pots with the same amount of fluid, so pedal travel is excessive. I upgraded mine, as the brake feel wasn't wonderful with the standard MC designed for use with the 266mm brakes.

Also, braided brake lines do nothing for this problem, they are only a worthy upgrade if you actually are getting brake fade or do a lot of fast-road driving / track work. Or if your rubber ones have perished and you fancy a bit of bling....