Valve cap solid copper ring for side valve (SV) engine with captive (non-removable) cylinder head. Suits Nortons pre c1932 for non-removable head. OD 2in (52mm); ID 1.75in (45.45mm); Th 0.080in (2mm). Als fits Norton OHV exhaust ring 1932+Original part number 5137 - Valve cap copper asbestos washer
