BSA B33 500CC 1948

1948 BSA B33 500CC PicturesBSA B33 500CC 1948The 1948 - 1950 BSA B33, for those of you not so familiar with it, was the big brother to BSA's post-war B31. The B31 ran 71mm x 88mm engine dimensions while the bigger bore B33 headed toward the nearly-square 85mm x 88mm. The 500cc bike gained a wider rear tyre, heavier flywheels and a larger inlet valve but was otherwise much the same as the 350.