Forget the OEM master cylinder ditch that thing. Get a Brembo master that corresponds to the piston size of your calipers (17RCS or 19RCS), stainless steel braded lines, good pads like Vesrah, Motul fluid and change out the bleed screws with Speed Bleeders (makes bleeding brake fluid so much easier). Out of all the upgrades you can do to a bike improving the front brakes are where it's at. It's a little investment at around $500 total if your keeping stock calipers. But, this is IMO the best money you can spend on an upgrade and at such an improvement it's almost like an upgraded insurance policy for your bike as it improves the braking feel and ability so much.
Brembo Front Master 290
Front SS brake lines 55
Front Pads 110
Motul Fluid 10
Speed bleeders 20
R6/R1 master would be better than oem gsxr but it would work best with R6/R1 monoblock calipers if you can find the set off someone for cheap. Just be aware of the piston size in the calipers as some are smaller or larger diameter if your going to mix a different bikes master with your bikes calipers because this effects the way the piston size in the master cylinder pushes fluid to caliper. This piston ratio creates the lever feel for the brakes (soft or firm). That's why you see 15, 17, 19 version masters.
Work Hard, Play Harder
Last edited by coreyyok; 11-06-2019 at 04:51 PM.