BSA B25-C25 / Triumph TR25W-T25SS Piston cplt std (Triumph no. 70-7998+71-1801 / BSA no. 40-970)
Condition: N.O.S. Made in Italy by GPM
Fits all: Triumph unit singles 1967-1972 & 250 BSA unit singles 1967-1972
Compr. Ratio: 9.5:1 Std size = 67 mm.