I am rebuilding my r90/6. When I purchased the bike it was unrideable. During the rebuild process, I rebuilt the master cylinder with new brake line, hydraulic line (SS), and all new o-rings and seals, the metal cylinder was cleaned, the piston was cleaned, and the chamber was honed. However, the plastic reservoir still leaks at the connection points to the metal cylinder. I believe the pitting on top of the cylinder is preventing the reservoir from sealing – but I am not positive. Any insight would be appreciated.