The O-ring(1wg) is the cheapest item from this partsfiche.
thirty-one components are shown in this C50trx 1999 Repair Kit 1 exploded diagram.
A sample from the products for the Repair Kit 1 include: Oil Seal, Gasket,fuel Pump (nas), Gasket, Oil Seal Housing (nas), Gasket, Valve Seat (nas).