On my last run out, I felt that my rear brake operation wasn't as it should be. A quick check confirmed that pressure on the foot lever was not transferring to the brake. Sticking calliper piston/s was my first thought but on further inspection, requiring disassembly of the footpeg and lever mechanism revealed that one of the two small countersuck retaining screws securing the push rod mechanism to the footpeg had worked loose and was fouling the footpeg bracket. The loose screw had gouged a score and created a lip (steel vs alluminium) in the footpeg mounting plate that prevented brake lever travel. Cleaning, thread lock and copper grease application now has restored full function to my rear brake. The moral of this tale is, Check your brake operation chums and if it's a bit 'sticky' don't assume it's the calliper!