No rear brakes on 02 cr250

After sitting for about four months my bike has no rear brakes. I have checked my fluid level and attemted to bleed the brake line but to no avail. The brake lever does not seem to have any pressure at all when aplied and only a small ammount of fluid came out while bleeding. Is the master cylinder rebuildable or might something else be amiss? any help would be apreciated as ther is a new track just ten minutes from the house that I am dying to get on. Thanks, Jb3636

I think your both right! I decided to take the master cylinder apart and see if I could clean things up and maybe revitalize the seals but no good, it just has no pressure. I just ordered the rebuild kit ($28.00) and the dis-assemble and re-assemble should be easy. Thanks for the replies as it allways helps to be reassured of what your thinking. Cheers