The most reasonably priced component used on the Cb1000r 2011 (b) France / Cmf St Rear Brake Mastercylinder is the Screw-washer,4x12.
A sample from the products for the Rear Brake Mastercylinder include: Bottom Comp., Bolt,flange,6x35, M/c Sub Assy,rr, Hose Comp B,rr Br.
The Rear Brake Mastercylinder is made up of components including this M/c Sub Assy,rr which is the most expensive.